Windows script debugger devenv.exe replaced by qnc.exe

I have software engineers with Visual Studio 6 sp4 development environment under NT 4sp6 with IE 5.5, and option pack for NT4. We installed Notes Client 5.03 to access a Domino 5.02 database. We did not have a problem until IE 5.5 makes a debug call and calls qnc.exe (lotus script debugger). It appears that Windows script debugger devenv.exe has been replaced by qnc.exe, so we ran qnc -u to uninstall qnc as the default debugger. We also reinstalled Visual Interdev 6.0sp4 and we get, DDE Server Window: devenv.exe - Application Error. The instruction at 0x77f7d064 referenced memory at 0x01056ab8. However, the memory could not be read. I have reviewed Microsoft KB articles, Lotus.net, Notes411, Webferret, Google etc... Do you have any ideas?
While getting rid of QNC was a good idea, somehow you need to reinstall Visual Studio.

This was first published in April 2001