diff --git a/include/cronjob.class.php b/include/cronjob.class.php
index bde76744f..f558807fc 100644
--- a/include/cronjob.class.php
+++ b/include/cronjob.class.php
@@ -364,7 +364,7 @@ class cronjob extends basis_db
 	public function execute()
 	{		
 		$return = true;
-		if($this->standalone && isJobRunning())
+		if($this->standalone && $this->isJobRunning())
 		{
 			$this->errormsg = 'Job kann nicht ausgefuehrt werden, da noch ein anderer Job laeuft';
 			return false;