Al -
I run an NT4 server with Fox 2.6 Dos with no problem (12 users).
One thing that came to mind was the files and buffers settings on both the server and workstations. I have all of my machines set to Files=200 and Buffers=60. Even though you are in Windows, the config.sys will still load.

Also (in your config.sys) place the command SHARE /L:500 /f:10240. Search for the Share program on you disk and path it to there. For example: it may be c:\Windows\System\share /L:500 /f:10240 (or something like that),

Remember to reboot your computer to make these changes take affect.

Let me know how you do.

Randy