The mechanics for a live char came with the forum. I think they work through IRC. It's in the menu bar at the top of the forum. I never set it up, so it doesn't work.
As for posting a message, I recently upgraded the forum software. Either it's a problem with the skin you're using, or it's a general error that cropped up with the upgrade. Try using one of the default skins and see if it that fixes it.