The "bad magic number" error usually indicates that the script was compiled for Python 1.5 as included with Poser 4 Pro Pack. The binary format changed with Python 2.0 (Poser 5 is using Python 2.2) which requires most scripts to be recompiled. If your have the source code for the script (.py files), delete or move the compiled version (.pyc) and Poser will recompile it from the original source file. If you don't have the source of the script, contact the script author for a Poser 5 compatible version.