Prior to morfing, you should test with a morf imported into blender, and exported unmodified . If the morf does not haywire, you can then proceed with the morfing but bearing in mind what pauljs75 said - only move existing vertices . Sometimes, however, haywiring is because of software settings - YZ axes switching and scaling should be turned off; local coordinates should be used . In yet other cases, the software exports vertices in reverse order, in which case, UVMapper can be used to unwind the vertices - I think . Hope this helps . :)