modified classes for GeneralException thrown

model/MongoDbCommand.php

@@ -38,7 +38,7 @@ abstract class MongoDbCommand
         if ($this->checkParams()) {
             return $this->concreteExecute();
         } else {
-            throw new Exception(get_called_class() . ' error. Bind all required params first.');
+            throw new GeneralException(get_called_class() . ' error. Bind all required params first.');
         }
     }