Maya 8.0 dts collision seems buggy

Geometry that I export with collisions work strangely. When I export a sphere the collision works properly. When I export a cube the collision either works poorly or not at all. I have noticed that the depth of the of the cube seems to effect ho well the collision works. The thiner the cube (e.g. a door type shape) the less likely the collision will work. I am using Maya 8 on Vista with the dts exporter compiled on 9/27/06. Any ideas or suggestions would be hugely appreciated.
-Tim