There is a bug in OS/2's DPMI server which is triggered by spawning child processes (like GCC does when it invokes the various compiler passes). If this problem really hurts, switch to real-mode GCC.EXE (get the file gccXXXrm.zip). Better still, yell at IBM to fix this, as Charles Sandmann, our DPMI wizard, tried in vain to convince them and gave up.