gistfile1.js

                    this.getWebuserDetailsStore().sync({
                        failure: function(batch, options) {
                            var errorCode = this.getReader().jsonData.error_code;
                            switch(errorCode) {
                                case 11: // Duplicate email
                                    var errorMessage = Translation.EmailAlreadyExistsPleaseUseAnother;
                                    break;
                                default:
                                    var errorMessage = Translation.AnErrorHasOccured;
                                    break;
                            }

                            Ext.defer(function() {
                                Ext.Msg.alert(Translation.Warning, errorMessage);
                            }, 50);
                        }
                    });