Thanks to you, Barbara, and to Vlad and Mark. My problem has been resolved.

It turned out that my problem was related to my expectation that code like..
m.x <> thisform.y
.. was going to tell me if the two were not equal.

Well, if thisform.y is "" while m.x is "wow", the expression evaluates to .F. making the system think they are the same. Duh! My brain must have been on a low ebb when I was considering this problem, since I didn't think of the operator's behavior well enough... Plus, I ignored the fact that my messageboxes did, in fact, fire in the valid code.

The fix was something like...
!m.x == thisform.y

This responds as expected. I think I was duped because the <> operator gave me what I wanted while in development environment, but not while in the .EXE environment. Thanks for the input.

Steve