That usually happens when it wants you to look for a bump map. It shows the file because it is probably a .jpg and needs converting to a bum. (do this in poser and not by renaming the file with a .bum extension) Correct me if I am wrong but does the following happen? If you cancel once it will ask if you want to continue looking, choose no it will then ask again for the file choose cancel and no. It then loads the MAT.