After I get Poquelin to open his dimension door and everyone gets transported to Easthaven, the game locks up. Everything on the menu is greyed out. I can however manipulate the dialogue screen, and time does pass since my buffs all expired while I was waiting for the game to come back.
Does anyone have any ideas on how to fix this?

Is the game patched???

Yes, patched up to 1.06

No offense, but why are you posting here? I mean, we love games and all but this is a pretty general forum and the game isn't even on GoG (yet?).
Try gibberlings3 forums or any of the other active infinity engine communities out there. Here's a link to the gibberling3 LINKS page, which lists most of them (the ones besides itself, obviously):
http://www.gibberlings3.net/links.php
I trust you can find your way from there? Good luck.

Ah, excellent! I tried a couple other forums for IWD but the links were dead. I'll check this one out, thanks.