Check out the thread "Application slows to a crawl on network" on 1999/02/06
It covers a very similar situtation.

>My application written in VFP5a run very slow in Win9x environment.
>We accessing the data using file server based.
>The application is run from a Win9x PC, accessing the file to be process from the Novell server.
>
>However, my similar old application written using clipper, running on DOS 6.22 with IPX/SPX run fast and fine, even though it access the file to be process from Novell server too.
>But, when I run the DOS application in the Win9x environment, the processing is also
>slow.
>