assertion failed in chvidimage3d.cpp 1397, game crash Options

[Gradius]

Hi guys, my game keeps on crashing and I'd appreciate your assistance.

I've installed the nej mod correctly, and everything's gone smoothly, until when I try to eastern exit in the area with the crazy goblin marshal (the area that you enter after the ice giants block the path back to easthaven) the game tries to load the next area then crashes:

assertion failed in chvidimage3d.cpp 1397
(and some message about trying to access a tile that wasn't loaded)

any help fixing the problem would be greatly appreciated. I was really getting into the story and the mod!

Chris