"Unable to start WOW."

Suddenly, I cannot print to fax from WordPerfect. When I try to select the WinFax 3.1 driver, NT gives this error message: Unable to start WOW. Verify the ability to run a Win 16 application and retry. I can run Win 16 applications (eg: MS Publisher)[and Task Manager shows that WOW loads under NTVDM.exe], and I have already checked the 10 files associated with "Cannot run 16 bit Windows program" error message. This used to run (a few days ago). I can run the WinFax program and "attach" the WP file, but this is cumbersome. The only program I have installed recently is Adobe Photoshop LE. Can anyone suggest what might be "broken"? Thanks.