Don,
You should check SET CENTURY, not SET DATE. My guess is one form has a private datasession while the other has a default datasession, for the command is scoped to the datasession, so try setting CENTURY in the form that is not working.
"The five senses obstruct or deform the apprehension of reality."
Jorge L. Borges?
"Premature optimization is the root of all evil in programming."
Donald Knuth, repeating C. A. R. Hoare
"To die for a religion is easier than to live it absolutely"
Jorge L. Borges