>VFP5 and VFP6 seem to both have trouble appending dates from a sdf file when the dates are mm/dd/yy or yy/dd/mm.

SET CENTURY doesn't affect how APPEND interprets text into dates. I don't think SET DATE does, either, I'm sure someone else will jump in if I'm wrong. I think your problem in VFP6 is probably SET STRICTDATE, although that doesn't apply to 5.0. See help on SET STRICTDATE. You want it to be 0 (zero) for date treatment like in 2.6. I don't know what your problem is in 5.0.