I am at the second summoning test in Act 4. I got stuck looking for the book, so went to the forums and noticed I need to talk to Tax. Small problem, Tax is stuck in a wall. I have noticed this problem a lot in the BF with the mobs, and only once with on of the merchants, however, I have always been able to work around it. Now, as far as I can tell, I am stuck in the game. I cannot progress any further and have no saved games before him getting stuck.
Is there any way to get him unstuck, or get one of my chars "stuck" in the same black area?