bugfix access property on null..

core/UI/Widget/DataTable/DataTable.php

@@ -211,8 +211,10 @@ class DataTable extends BaseContainer implements \ModulesGarden\Servers\ZimbraEm
             return $this;
         }
         
-        $row->$colName = $value;
-
+        if (is_object($row))
+        {
+           $row->$colName = $value;
+        }
         return $this;        
     }