do you have a normal map? I'd suggest double checking spelling. Also, I presume that the new texture works well in Nifskope? What if you equip your new robe in the CK, does it crash it as well? Also, I'd check whther it is set right in the NifSkope, both colour and normal maps in their appropriate place. Lastly, did you save the texture in the right format, mip maps and all?
These are the things that I can think of off the top of my head.
Hope this helps