Try using the 2.2 SNAPSHOT and see if that makes a difference. There have been some fixes with cron triggers in the past that have been fixed in the latest.
But from what I see the cron trigger you currently have should be triggering the rule every fourth second of each minute. (e.g. 10:36:04).
Do you see any errors in the logs?
Is the rule truly not triggering or could there be a problem with your lock not being unlocked properly? Do you really need the lock?