Thanks for the unbelievably quick response Hilary! (side note: I have an Aunt Hilary - used to call her Ant Hill)
Yes - I have code with my form, but I commented all the code out and still the same problem.
I can check the SP logs, but it doesn't log anything during Designer Checker, does it?
I have a bunch of forms it is now not working with. If I create a brand new form, no issues. Uploaded & approved.
What credentials does it use to go off and verify the code will work on the site? How do I change those credentials?
Chris ... er, Arthur Fonzarelli!