Wow, I'm suprised you can upgrade from that far back, even I don't have to program in 2.6!
I'm afraid I don't know why this would be happening; but all I can suggest is rebuilding the forms (yeah, I know, bit of a cop out).
I can't believe I missed this post; it's rare we have questions about VFP!
Good luck, let us know if you find a solution or not
P.S. have you heard? VFP 9.0 will be the last release of FP
