Are you adding tiles to the CEP Forest? If so, you will need to add the new tiles to the CEP .set and .itp files. IIRC the
Tileset Group Tutorial has a good discussion of .set and .itp (you can skip the model-making steps).
If you're adding the new tiles to the Bioware Forest, check that the .set and .itp files are the 1.69 versions plus the new tiles, if not, add the new tiles to the 1.69 version. (Though judging by the date, that shouldn't be a problem).
I note it talks about merging with the Treehouse_susp hak, so you might need to integrate that, too.
Can't be sure this is why the module is crashing, of course.