A MATpose by-passes the convert step. If you use a MATpose that calls for a bump.jpg, in P4, and you have the JPEG, the result will be a sooty figure in the render. If you use a MATpose that calls for a bump.BUM and you do not have the file - only the bump.jpg - you get the freeze/crash. The bump.BUM must be generated before you use the MATpose. You must do it the traditional way - apply the bump.jpg to a material in the Material window - by hand. This is when Poser converts the file to *.BUM. The figure and material do not matter, you just need one to do the conversion. I don't know what PPP does about conversion, but it will use a bump.jpg directly, so you are better off making sure the MATpose calls for a *.jpg instead of a *.BUM if you do not have the converted file - save the hd space.