I just tried what you said, and when i got into a wild pokemon battle with gulpin(lucario) and the screen went pitch black. I then went into pokemon editor pro and changed the image offsets for gulpin to the new ones it had in the top right of unlz, and went to meet gulpin again, this time though, it just showed the sprite of the messed up gulpin.
EDIT: I tried it again but with swalot and a darkrai sprite, this is this the result:
http://i240.photobucket.com/albums/f...30/problem.jpg