You may need except the Fast Processor (Division by zero) patch, some other ones:
FoxPro 2.6a Patch Files
http://users.aol.com/FoxProResources/fp26a.htm

PATCH: Patch_26.exe Fixes Divide by Zero Error on Fast Computers (Q240982)
http://support.microsoft.com/default.aspx?scid=kb;EN-US;q240982

PATCH: FoxPro 2.6a Patch Files for FoxPro 2.6 (Q102893)
http://support.microsoft.com/default.aspx?scid=kb;EN-US;q102893

FP2.6 apps works better and faster on computers with CPU PII<333
To use P4 computer was not the best decision. If you like to use that processor convert your apps in VFP7.0.

HTH