NONMEM using OS/2 Warp

I am puzzled by your problem. I use OS/2 (v 2.1) and have never had a problem running DOS programs except those that try to do strange things to the video. I use the Watcom 77 compiler for NONMEM because it makes OS/2 executables as well as DOS executables. I have no experience with Powerstation. Have you tried running the Powerstation executable from a OS/2 DOS full screen session? Or only from an OS/2 DOS window? You might see an error message before it crashes if you use full screen.