diff --git a/workflow/engine/classes/class.processes.php b/workflow/engine/classes/class.processes.php
index 9e72e699c..d688ea0a3 100755
--- a/workflow/engine/classes/class.processes.php
+++ b/workflow/engine/classes/class.processes.php
@@ -2426,12 +2426,14 @@ class Processes
      */
     public function createTaskUserRows ($aTaskUser)
     {
-        foreach ($aTaskUser as $key => $row) {
-            $oTaskUser = new TaskUser();
-            if ($oTaskUser->TaskUserExists( $row['TAS_UID'], $row['USR_UID'], $row['TU_TYPE'], $row['TU_RELATION'] )) {
-                $oTaskUser->remove( $row['TAS_UID'], $row['USR_UID'], $row['TU_TYPE'], $row['TU_RELATION'] );
+        if (is_array($aTaskUser)) {
+            foreach ($aTaskUser as $key => $row) {
+                $oTaskUser = new TaskUser();
+                if ($oTaskUser->TaskUserExists( $row['TAS_UID'], $row['USR_UID'], $row['TU_TYPE'], $row['TU_RELATION'] )) {
+                    $oTaskUser->remove( $row['TAS_UID'], $row['USR_UID'], $row['TU_TYPE'], $row['TU_RELATION'] );
+                }
+                $res = $oTaskUser->create( $row );
             }
-            $res = $oTaskUser->create( $row );
         }
         return;
     }
diff --git a/workflow/engine/methods/users/usersAjax.php b/workflow/engine/methods/users/usersAjax.php
index 64ddb4166..903ec5899 100644
--- a/workflow/engine/methods/users/usersAjax.php
+++ b/workflow/engine/methods/users/usersAjax.php
@@ -130,7 +130,7 @@ switch ($_POST['action']) {
             if ($form['USR_UID'] == '') {
                 $criteria = new Criteria();
                 $criteria->addSelectColumn(UsersPeer::USR_USERNAME);
-                $criteria->add(UsersPeer::USR_USERNAME, $_POST['USR_USERNAME']);
+                $criteria->add(UsersPeer::USR_USERNAME, utf8_encode($_POST['USR_USERNAME']));
                 if (UsersPeer::doCount($criteria) > 0) {
                     throw new Exception(G::LoadTranslation('ID_USERNAME_ALREADY_EXISTS', array('USER_ID' => $_POST['USR_USERNAME'])));
                 }
@@ -584,7 +584,7 @@ switch ($_POST['action']) {
         $oCriteria = new Criteria();
         $oCriteria->addSelectColumn(UsersPeer::USR_USERNAME);
 
-        $oCriteria->add(UsersPeer::USR_USERNAME, $_POST['NEW_USERNAME']);
+        $oCriteria->add(UsersPeer::USR_USERNAME, utf8_encode($_POST['NEW_USERNAME']));
         if ($USR_UID != '') {
             $oCriteria->add(UsersPeer::USR_UID, array($_POST['USR_UID']), Criteria::NOT_IN);
         }