diff --git a/lib/scalatra-forms_2.10-0.0.2.jar b/lib/scalatra-forms_2.10-0.0.2.jar
new file mode 100644
index 0000000..ced430a
--- /dev/null
+++ b/lib/scalatra-forms_2.10-0.0.2.jar
Binary files differ
diff --git a/project/build.scala b/project/build.scala
index cc8251e..4f0d9df 100644
--- a/project/build.scala
+++ b/project/build.scala
@@ -32,7 +32,7 @@
         "org.scalatra" %% "scalatra-specs2" % ScalatraVersion % "test",
         "org.scalatra" %% "scalatra-json" % ScalatraVersion,
         "org.json4s" %% "json4s-jackson" % "3.2.4",
-        "jp.sf.amateras" %% "scalatra-forms" % "0.0.1",
+//        "jp.sf.amateras" %% "scalatra-forms" % "0.0.1",
         "commons-io" % "commons-io" % "2.4",
         "org.pegdown" % "pegdown" % "1.3.0",
         "org.apache.commons" % "commons-compress" % "1.5",
diff --git a/src/main/scala/app/ControllerBase.scala b/src/main/scala/app/ControllerBase.scala
index c359ff2..ffbf7c2 100644
--- a/src/main/scala/app/ControllerBase.scala
+++ b/src/main/scala/app/ControllerBase.scala
@@ -167,12 +167,12 @@
   }
 
   protected def uniqueUserName: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
+    override def validate(name: String, value: String): Option[String] =
       getAccountByUserName(value).map { _ => "User already exists." }
   }
 
   protected def uniqueMailAddress(paramName: String = ""): Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
+    override def validate(name: String, value: String, params: Map[String, String]): Option[String] =
       getAccountByMailAddress(value)
         .filter { x => if(paramName.isEmpty) true else Some(x.userName) != params.get(paramName) }
         .map    { _ => "Mail address is already registered." }
diff --git a/src/main/scala/app/CreateRepositoryController.scala b/src/main/scala/app/CreateRepositoryController.scala
index 5180bb7..0a9ebe7 100644
--- a/src/main/scala/app/CreateRepositoryController.scala
+++ b/src/main/scala/app/CreateRepositoryController.scala
@@ -180,7 +180,7 @@
   }
 
   private def existsAccount: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
+    override def validate(name: String, value: String): Option[String] =
       if(getAccountByUserName(value).isEmpty) Some("User or group does not exist.") else None
   }
 
@@ -188,7 +188,7 @@
    * Duplicate check for the repository name.
    */
   private def unique: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
+    override def validate(name: String, value: String, params: Map[String, String]): Option[String] =
       params.get("owner").flatMap { userName =>
         getRepositoryNamesOfUser(userName).find(_ == value).map(_ => "Repository already exists.")
       }
diff --git a/src/main/scala/app/LabelsController.scala b/src/main/scala/app/LabelsController.scala
index e666d67..1366c4c 100644
--- a/src/main/scala/app/LabelsController.scala
+++ b/src/main/scala/app/LabelsController.scala
@@ -51,7 +51,7 @@
    * Constraint for the identifier such as user name, repository name or page name.
    */
   private def labelName: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
+    override def validate(name: String, value: String): Option[String] =
       if(!value.matches("^[^,]+$")){
         Some(s"${name} contains invalid character.")
       } else if(value.startsWith("_") || value.startsWith("-")){
diff --git a/src/main/scala/app/RepositorySettingsController.scala b/src/main/scala/app/RepositorySettingsController.scala
index 14c4f91..a647930 100644
--- a/src/main/scala/app/RepositorySettingsController.scala
+++ b/src/main/scala/app/RepositorySettingsController.scala
@@ -112,7 +112,7 @@
    * Provides Constraint to validate the collaborator name.
    */
   private def collaborator: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] = {
+    override def validate(name: String, value: String): Option[String] = {
       val paths = request.getRequestURI.split("/")
       getAccountByUserName(value) match {
         case None => Some("User does not exist.")
diff --git a/src/main/scala/app/SystemSettingsController.scala b/src/main/scala/app/SystemSettingsController.scala
index a8f87e9..0e824c4 100644
--- a/src/main/scala/app/SystemSettingsController.scala
+++ b/src/main/scala/app/SystemSettingsController.scala
@@ -16,16 +16,13 @@
     "allowAccountRegistration" -> trim(label("Account registration", boolean())),
     "gravatar"                 -> trim(label("Gravatar", boolean())),
     "notification"             -> trim(label("Notification", boolean())),
-    "smtp"                     -> mapping(
-        "host"     -> trim(label("SMTP Host", text(new Constraint(){
-          def validate(name: String, value: String): Option[String] =
-            if(params.get("notification").exists(_ == "on")) required.validate(name, value) else None
-        }))),
+    "smtp"                     -> optionalIfNotChecked("notification", mapping(
+        "host"     -> trim(label("SMTP Host", text(required))),
         "port"     -> trim(label("SMTP Port", optional(number()))),
         "user"     -> trim(label("SMTP User", optional(text()))),
         "password" -> trim(label("SMTP Password", optional(text()))),
         "ssl"      -> trim(label("Enable SSL", optional(boolean())))
-    )(Smtp.apply)
+    )(Smtp.apply))
   )(SystemSettings.apply)
 
 
diff --git a/src/main/scala/app/WikiController.scala b/src/main/scala/app/WikiController.scala
index c1c1feb..c18c473 100644
--- a/src/main/scala/app/WikiController.scala
+++ b/src/main/scala/app/WikiController.scala
@@ -136,12 +136,12 @@
   })
 
   private def unique: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
+    override def validate(name: String, value: String, params: Map[String, String]): Option[String] =
       getWikiPageList(params("owner"), params("repository")).find(_ == value).map(_ => "Page already exists.")
   }
 
   private def pagename: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
+    override def validate(name: String, value: String): Option[String] =
       if(value.exists("\\/:*?\"<>|".contains(_))){
         Some(s"${name} contains invalid character.")
       } else if(value.startsWith("_") || value.startsWith("-")){
diff --git a/src/main/scala/service/SystemSettingsService.scala b/src/main/scala/service/SystemSettingsService.scala
index 0d63f6e..6837f70 100644
--- a/src/main/scala/service/SystemSettingsService.scala
+++ b/src/main/scala/service/SystemSettingsService.scala
@@ -11,11 +11,13 @@
     props.setProperty(Gravatar, settings.gravatar.toString)
     props.setProperty(Notification, settings.notification.toString)
     if(settings.notification) {
-      props.setProperty(SmtpHost, settings.smtp.host)
-      settings.smtp.port.foreach(x => props.setProperty(SmtpPort, x.toString))
-      settings.smtp.user.foreach(props.setProperty(SmtpUser, _))
-      settings.smtp.password.foreach(props.setProperty(SmtpPassword, _))
-      settings.smtp.ssl.foreach(x => props.setProperty(SmtpSsl, x.toString))
+      settings.smtp.foreach { smtp =>
+        props.setProperty(SmtpHost, smtp.host)
+        smtp.port.foreach(x => props.setProperty(SmtpPort, x.toString))
+        smtp.user.foreach(props.setProperty(SmtpUser, _))
+        smtp.password.foreach(props.setProperty(SmtpPassword, _))
+        smtp.ssl.foreach(x => props.setProperty(SmtpSsl, x.toString))
+      }
     }
     props.store(new java.io.FileOutputStream(GitBucketConf), null)
   }
@@ -30,13 +32,17 @@
       getValue(props, AllowAccountRegistration, false),
       getValue(props, Gravatar, true),
       getValue(props, Notification, false),
-      Smtp(
-        getValue(props, SmtpHost, ""),
-        getOptionValue(props, SmtpPort, Some(25)),
-        getOptionValue(props, SmtpUser, None),
-        getOptionValue(props, SmtpPassword, None),
-        getOptionValue[Boolean](props, SmtpSsl, None)
-    ))
+      if(getValue(props, Notification, false)){
+        Some(Smtp(
+          getValue(props, SmtpHost, ""),
+          getOptionValue(props, SmtpPort, Some(25)),
+          getOptionValue(props, SmtpUser, None),
+          getOptionValue(props, SmtpPassword, None),
+          getOptionValue[Boolean](props, SmtpSsl, None)))
+      } else {
+        None
+      }
+    )
   }
 
 }
@@ -48,7 +54,7 @@
     allowAccountRegistration: Boolean,
     gravatar: Boolean,
     notification: Boolean,
-    smtp: Smtp
+    smtp: Option[Smtp]
   )
   case class Smtp(
     host: String,
diff --git a/src/main/scala/util/Validations.scala b/src/main/scala/util/Validations.scala
index dd383e3..cb92c0d 100644
--- a/src/main/scala/util/Validations.scala
+++ b/src/main/scala/util/Validations.scala
@@ -8,7 +8,7 @@
    * Constraint for the identifier such as user name, repository name or page name.
    */
   def identifier: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
+    override def validate(name: String, value: String): Option[String] =
       if(!value.matches("^[a-zA-Z0-9\\-_]+$")){
         Some(s"${name} contains invalid character.")
       } else if(value.startsWith("_") || value.startsWith("-")){
diff --git a/src/main/twirl/admin/system.scala.html b/src/main/twirl/admin/system.scala.html
index b2a91ca..9d8c9b6 100644
--- a/src/main/twirl/admin/system.scala.html
+++ b/src/main/twirl/admin/system.scala.html
@@ -39,33 +39,33 @@
             <div class="control-group">
               <label class="control-label" for="smtpHost">SMTP Host</label>
               <div class="controls">
-                <input type="text" id="smtpHost" name="host" value="@settings.smtp.host"/>
-                <span id="error-host" class="error"></span>
+                <input type="text" id="smtpHost" name="smtp.host" value="@settings.smtp.map(_.host)"/>
+                <span id="error-smtp_host" class="error"></span>
               </div>
             </div>
             <div class="control-group">
               <label class="control-label" for="smtpPort">SMTP Port</label>
               <div class="controls">
-                <input type="text" id="smtpPort" name="port" class="input-mini" value="@settings.smtp.port"/>
-                <span id="error-port" class="error"></span>
+                <input type="text" id="smtpPort" name="smtp.port" class="input-mini" value="@settings.smtp.map(_.port)"/>
+                <span id="error-smtp_port" class="error"></span>
               </div>
             </div>
             <div class="control-group">
               <label class="control-label" for="smtpUser">SMTP User</label>
               <div class="controls">
-                <input type="text" id="smtpUser" name="user" value="@settings.smtp.user"/>
+                <input type="text" id="smtpUser" name="smtp.user" value="@settings.smtp.map(_.user)"/>
               </div>
             </div>
             <div class="control-group">
               <label class="control-label" for="smtpPassword">SMTP Password</label>
               <div class="controls">
-                <input type="password" id="smtpPassword" name="password" value="@settings.smtp.password"/>
+                <input type="password" id="smtpPassword" name="smtp.password" value="@settings.smtp.map(_.password)"/>
               </div>
             </div>
             <div class="control-group">
               <div class="controls">
                 <label class="checkbox">
-                  <input type="checkbox" name="ssl"@if(settings.smtp.ssl == Some(true)){ checked}/> Enable SSL
+                  <input type="checkbox" name="smtp.ssl"@if(settings.smtp.flatMap(_.ssl).getOrElse(false)){ checked}/> Enable SSL
                 </label>
               </div>
             </div>
diff --git a/src/main/webapp/assets/common/js/validation.js b/src/main/webapp/assets/common/js/validation.js
index fc9875c..2840677 100644
--- a/src/main/webapp/assets/common/js/validation.js
+++ b/src/main/webapp/assets/common/js/validation.js
@@ -34,6 +34,6 @@
 
 function displayErrors(data){
   $.each(data, function(key, value){
-    $('#error-' + key).text(value);
+    $('#error-' + key.split('.').join('_')).text(value);
   });
 }
\ No newline at end of file