Craig,
I will be glad to post my PK code if you will (forgive my ignorance) tell me what you mean by PK. I think you mean the transaction code I use to post with. It is in the form:( I do not have the code at hand but I believe this is accurate)
begin transaction
select table
lsuccess=tableupdate(.t.,.t.)
if lsuccess
select table
lsuccess=tableupdate(.t.,.t.)
...
if lsuccess
endtrans
else
rollback
tell user something bad happened.
endif
I am almost certain that this succeeds, but that at some point the record count in one or more tables is corrupt so that the next time through some previous records get overwritten.

As far as the primary key problem is concerned I have no idea what is happening. When I examine users error logs I do not see anything that would cause this. I remember that when I first started working with VFP I was able form time to time to screw up a primary key but it was always after a long series of errors usually terminated by several CtrlAltdeletes.
Any suggestions would be most helpful.

Thanks.