Almost sounds like a PMD corruption.  RHaseltine has suggested some potential fixes; I would check how your files are installed.  We either are seeing file conflicts, bad settings, or operating system interference.  

Give us a better idea how files are installed and under which OS you are running Poser.  Also post which Poser version you are running.

Edit: There are several Service Releases for P7 @ SmithMicro you should dl and install.  Those will fix certain issues.