diff --git a/cake/libs/model/datasources/dbo_source.php b/cake/libs/model/datasources/dbo_source.php
index f7fd157bc..5e2e73b5a 100644
--- a/cake/libs/model/datasources/dbo_source.php
+++ b/cake/libs/model/datasources/dbo_source.php
@@ -1669,7 +1669,8 @@ class DboSource extends DataSource {
  */
 	function __destruct() {
 		if ($this->_transactionStarted) {
-			$this->rollback();
+			$null = null;
+			$this->rollback($null);
 		}
 		$this->close();
 		parent::__destruct();