What do you mean by "hang up" - does it freeze? If a BUM is missing from a file, Poser will/should ask to locate it. If it already is a .bum file, PPP should take it as it is, and for any other format it will convert it every time it renders (instead of writing out a new .bum like Poser1-4). If you don't have any file - no BUM, no TIF, no whatever - then you're just as lost as any other Poser user.