John,
Thanks very much for your reply. The "Not Empty" box was checked under Validation in the Field Options. I don't think this could be changed from the layout.
I did bring up the layout in the new window and tried changing the field. That didn't work, but it did result in a different message, something about the value being required, but that it couldn't be edited on this layout so I was supposed to enter it on a different layout.
I don't know if it next came up on its own, or because i hit something (Esc?), but it then gave me the option to Revert the Record. That did the trick! It deleted (un-created?) the record and let me out of the endless loop!
Good stuff. Thanks again for your prompt reply, and the assistance. Cheers!
Michael