I'd be interested in knowing too!

Early in development in VFP3 we found that there were problems in updating when the primary key was not exactly the same length in VFP and Oracle.

eg. VFP char field c(10) containing '17' <> Oracle VARCHAR2(10) containing '17'

We found that by padding the pk with zeros until both were 10 in length solved the problem.

ie. VFP C(10) '0000000017' = Oracle VARCHAR2(10) '0000000017'

I presume this is not the problem in your case as you say things worked OK in VFP 5. Still it would be worth double checking...