diff --git a/scm-webapp/src/main/webapp/resources/js/sonia.config.js b/scm-webapp/src/main/webapp/resources/js/sonia.config.js
index 3295a85bd3..bcedd40277 100644
--- a/scm-webapp/src/main/webapp/resources/js/sonia.config.js
+++ b/scm-webapp/src/main/webapp/resources/js/sonia.config.js
@@ -139,7 +139,12 @@ Sonia.config.ScmConfigPanel = Ext.extend(Sonia.config.ConfigPanel,{
             failure: function(){
               el.unmask();
               clearTimeout(tid);
-              alert('failure');
+              Ext.MessageBox.show({
+                title: 'Error',
+                msg: 'Could not load config.',
+                buttons: Ext.MessageBox.OK,
+                icon:Ext.MessageBox.ERROR
+              });
             }
           });
         }
diff --git a/scm-webapp/src/main/webapp/resources/js/sonia.plugin.js b/scm-webapp/src/main/webapp/resources/js/sonia.plugin.js
index c6a60bb73d..fa6b908fc5 100644
--- a/scm-webapp/src/main/webapp/resources/js/sonia.plugin.js
+++ b/scm-webapp/src/main/webapp/resources/js/sonia.plugin.js
@@ -90,8 +90,13 @@ Sonia.plugin.installPlugin = function(pluginId){
       if ( debug ){
         console.debug('plugin installation failed');
       }
-      alert( 'failure' );
       loadingBox.hide();
+      Ext.MessageBox.show({
+        title: 'Error',
+        msg: 'Plugin installation failed',
+        buttons: Ext.MessageBox.OK,
+        icon:Ext.MessageBox.ERROR
+      });
     }
   });
 }
@@ -127,8 +132,13 @@ Sonia.plugin.uninstallPlugin = function(pluginId){
       if ( debug ){
         console.debug('plugin uninstallation failed');
       }
-      alert( 'failure' );
       loadingBox.hide();
+      Ext.MessageBox.show({
+        title: 'Error',
+        msg: 'Plugin uninstallation failed',
+        buttons: Ext.MessageBox.OK,
+        icon:Ext.MessageBox.ERROR
+      });
     }
   });
 }
@@ -162,10 +172,15 @@ Sonia.plugin.updatePlugin = function(pluginId){
     },
     failure: function(){
       if ( debug ){
-        console.debug('plugin updated failed');
+        console.debug('plugin update failed');
       }
-      alert( 'failure' );
       loadingBox.hide();
+      Ext.MessageBox.show({
+        title: 'Error',
+        msg: 'Plugin update failed',
+        buttons: Ext.MessageBox.OK,
+        icon:Ext.MessageBox.ERROR
+      });
     }
   });
 }
diff --git a/scm-webapp/src/main/webapp/resources/js/sonia.repository.js b/scm-webapp/src/main/webapp/resources/js/sonia.repository.js
index bedd122b73..a92abe6a17 100644
--- a/scm-webapp/src/main/webapp/resources/js/sonia.repository.js
+++ b/scm-webapp/src/main/webapp/resources/js/sonia.repository.js
@@ -357,7 +357,12 @@ Sonia.repository.FormPanel = Ext.extend(Sonia.rest.FormPanel,{
       failure: function(){
         clearTimeout(tid);
         el.unmask();
-        alert( 'failure' );
+        Ext.MessageBox.show({
+          title: 'Error',
+          msg: 'Repository update failed',
+          buttons: Ext.MessageBox.OK,
+          icon:Ext.MessageBox.ERROR
+        });
       }
     });
   },
@@ -390,7 +395,12 @@ Sonia.repository.FormPanel = Ext.extend(Sonia.rest.FormPanel,{
       failure: function(){
         clearTimeout(tid);
         el.unmask();
-        alert( 'failure' );
+        Ext.MessageBox.show({
+          title: 'Error',
+          msg: 'Repository creation failed',
+          buttons: Ext.MessageBox.OK,
+          icon:Ext.MessageBox.ERROR
+        });
       }
     });
   },
@@ -486,7 +496,12 @@ Sonia.repository.Panel = Ext.extend(Ext.Panel, {
                 this.resetPanel();
               },
               failure: function(){
-                alert( 'failure' );
+                Ext.MessageBox.show({
+                  title: 'Error',
+                  msg: 'Repository deletion failed',
+                  buttons: Ext.MessageBox.OK,
+                  icon:Ext.MessageBox.ERROR
+                });
               }
             });
           }
diff --git a/scm-webapp/src/main/webapp/resources/js/sonia.rest.js b/scm-webapp/src/main/webapp/resources/js/sonia.rest.js
index fa5adf7fe8..6b90d9f96a 100644
--- a/scm-webapp/src/main/webapp/resources/js/sonia.rest.js
+++ b/scm-webapp/src/main/webapp/resources/js/sonia.rest.js
@@ -47,7 +47,12 @@ Sonia.rest.JsonStore = Ext.extend( Ext.data.JsonStore, {
               }
               this.removeAll();
             } else {
-              alert( action + "(" + status + "): " + response.responseText );
+              Ext.MessageBox.show({
+                title: 'Error',
+                msg: 'Could not load items. Server returned status: ' + status,
+                buttons: Ext.MessageBox.OK,
+                icon:Ext.MessageBox.ERROR
+              });
             }
           },
           scope: this
diff --git a/scm-webapp/src/main/webapp/resources/js/sonia.user.js b/scm-webapp/src/main/webapp/resources/js/sonia.user.js
index cd0d23dcc8..b32aefdeb7 100644
--- a/scm-webapp/src/main/webapp/resources/js/sonia.user.js
+++ b/scm-webapp/src/main/webapp/resources/js/sonia.user.js
@@ -207,7 +207,12 @@ Sonia.user.FormPanel = Ext.extend(Sonia.rest.FormPanel,{
         this.execCallback(this.onUpdate, item);
       },
       failure: function(){
-        alert( 'failure' );
+        Ext.MessageBox.show({
+          title: 'Error',
+          msg: 'User update failed',
+          buttons: Ext.MessageBox.OK,
+          icon:Ext.MessageBox.ERROR
+        });
       }
     });
     
@@ -233,7 +238,12 @@ Sonia.user.FormPanel = Ext.extend(Sonia.rest.FormPanel,{
         this.execCallback(this.onCreate, user);
       },
       failure: function(){
-        alert( 'failure' );
+        Ext.MessageBox.show({
+          title: 'Error',
+          msg: 'User creation failed',
+          buttons: Ext.MessageBox.OK,
+          icon:Ext.MessageBox.ERROR
+        });
       }
     });
   },
@@ -343,7 +353,12 @@ Sonia.user.Panel = Ext.extend(Ext.Panel, {
                 this.resetPanel();
               },
               failure: function(){
-                alert( 'failure' );
+                Ext.MessageBox.show({
+                  title: 'Error',
+                  msg: 'User deletion failed',
+                  buttons: Ext.MessageBox.OK,
+                  icon:Ext.MessageBox.ERROR
+                });
               }
             });
           }