Followup for those with similar problems...
I ran into the same problem on NT 4.0 SP 6a with 2.6 Apps, the final solution was us to add the following lines to our autoexec.nt (in system32 dir). I found this by comparing systems which worked properly vs. systems which weren't working, thanks to other responses for pointing me in the right direction!.

lh %SystemRoot%\system32\nw16
lh %SystemRoot%\system32\vwipxspx

This has worked on our workstations, which use Novell, and client's systems w/o Novell; maybe someone can shed some light on these files...

---

>A client installed Windows 2000 Professional Release Candidate 2 (October 1999) and our payroll and financial applications don't run (the screen just gives a quick flicker, then returns to the desktop). Tried FOXSTART.EXE (the freeware CPU hog that allows the previous fpw2600.esl to run on fast pentiums) as suggested in foxforum, but that didn't work.