>If I try to use a form in VFP and it starts converting, whether functional or visual, and regardless of whether the source form is from 2.6 for DOS or Windows, I always get this message. Any ideas how to resolve this problem, without recreating my forms altogether.

You open the 2.6 project (.pjx) under VFP5/6 and you should see the conversion options. If you didn't have a 2.6 project file, they're pretty easy to create.
HTH