You didn't give quite enough of the error message.
Are you trying to access /chat/moderate.tcl when you see this?
At first glance, I don't see how this could ever have worked (I'm looking at the ACS 3.2.5 version.) At the time chat_get_posts_to_moderate is called, the tcl page moderate.tcl already has a handle (presumably from main). If so, then chat_get_posts_to_moderate should almost certainly fail as AOLserver doesn't let you allocate multiple handles from the same pool within a page unless you allocate them all in the same call.
If so, the fix would be to pass the db handle into the proc.
