If you're using P4's RIB export with BMRT, you need to do a search/replace to replace all the characters with . BMRT is expecting texture paths in C-style strings, where most other renderers I've seen use a single backslash in paths on Windows. However, my exporter won't help you much as it's written in Python and using some of Poser 5's methods, so it wouldn't even run on ProPack without modification. But the good part is that I can already export full animations to a series or RIB files that are being rendered in the background - great for animation previews!