On all of my development machines I have installed FPD 2.6, FPW 2.6, VFP6, & VFP7 with no cross-"contamination" or operational interference.
Are the VFP and the FPW application running concurrently within any single workstation when the problems appear?
If not... Never mind.
If so... Are the problems present when only one of the FP's is operating?
Foxpro (visual or not) loves memory and will take all that it can when running an application. Two instances of Foxpro on a workstation would attempt to take even more. That sometimes leaves little remaining for other workstation operations resulting in a whole host of "quirky" problems.
If this client is like some offices I have seen the users are concurrently running 5 Excel spreadsheets, Internet Explorer, Outlook, Word and also one or more FP application(s). Somewhere along the line a limit is passed and problems abound.
That is not to say that a Foxpro application can not co-exist and run concurrently with other applications, but perhaps this is an instance where you are running out of memory or CPU resources.
Good Luck,
JRB-Bldr
VisionQuest Consulting
Business Analyst & CIO Consulting Services
CIOServices@yahoo.com