Fixed to prevent custom message from being overidden by default

Doctrine/Table/Exception.php

@@ -5,10 +5,10 @@ Doctrine::autoload('Doctrine_Exception');
  * while there already exists an instance of that table
  */
 class Doctrine_Table_Exception extends Doctrine_Exception {
-    public function __construct() {
-        parent::__construct("Couldn't initialize table. One instance of this
+    public function __construct($message = "Couldn't initialize table. One instance of this
                             table already exists. Always use Doctrine_Session::getTable(\$name)
-                            to get on instance of a Doctrine_Table.",Doctrine::ERR_TABLE_INSTANCE);
+                            to get on instance of a Doctrine_Table.") {
+        parent::__construct($message,Doctrine::ERR_TABLE_INSTANCE);
     }
 }