diff --git a/management/univention-web/js/tools.js b/management/univention-web/js/tools.js
index 70de553..0795200 100644
--- a/management/univention-web/js/tools.js
+++ b/management/univention-web/js/tools.js
@@ -677,11 +677,12 @@ define([
 					this.umcpProgressSubCommand({
 						progressCmd: progressCmd,
 						progressID: progressID,
-						flavor: flavor
+						flavor: flavor,
+						errorHandler: errorHandler
 					}).then(function() {
-							deferred.resolve(allData);
-					}, function() {
-						deferred.reject();
+						deferred.resolve(allData);
+					}, function(error) {
+						deferred.reject(error);
 					}, function(result) {
 						allData = allData.concat(result.intermediate);
 						if (result.percentage === 'Infinity') { // FIXME: JSON cannot handle Infinity
@@ -694,8 +695,8 @@ define([
 						}
 					});
 				}),
-				function() {
-					deferred.reject(arguments);
+				function(error) {
+					deferred.reject(tools.parseError(error));
 				}
 			);
 			return deferred;
@@ -715,8 +716,8 @@ define([
 						setTimeout(lang.hitch(this, 'umcpProgressSubCommand', lang.mixin({}, props, {deferred: deferred}), 200));
 					}
 				}),
-				function() {
-					deferred.reject();
+				function(error) {
+					deferred.reject(tools.parseError(error));
 				}
 			);
 			return deferred;