That happens when nobody posts to a thread for too long. Send a PM to one of the admins to get it unlocked.
I found Bangkok 57 not bad. The key here is to remove the stickies below the lightnings. Concentrate on one, then make a match below the lightning so that it drops. If there's a way to make a combo in that area that is ideal, because swapping lightning with the combo will rack up points and clear a layer of stickies. I'm not sure whether it is best to use the freed lightning immediately if you have no combo near it, or to save it.