The program isn't crashing, it just says "Specified package(s) has no supported objects".
I uploaded some files here:
http://www.mediafire.com/?6z5pfcyxpn68g8uBut I couldn't find the GFxUI.pcc or any other pcc files for that matter, just an ini for the UI files. I also don't know if there really is a swf file integrated or compressed in the upks, but the file's last line suggests it.
The main reason I'm interested in these files is because I want to extract the achievement images for the wiki. These images doesn't seem to be simple textures, because then I would've had no problem extracting them with your program or filter them with texmod.
If you could help me any further on this matter, I would be really grateful, but I don't want to waste your time. Thanks.