Hi y'all! Yes, PBooost 1.3 is just compatible with Poser 4, but PBooost 1.4 is nearly ready... If you have 1.3 and wish to use it with Poser 5, or Pro Pack with compressed content, let me know your e-mail and I'll send you the update! Ernyoka1...you have the 1.4 update already! That's why it works with Poser 5! Phew... better get back to writing the instructions! LOL! Howard:))