I have thought about it, and listing all of the code in sequence would not have pointed out my problem in this situation. It may have given me some idea of line number, but it would not have helped.

With that in mind, are there any better ways to help see these obscure problems?
The whole point of this thread was to help identify troubleshooting techniques.
In this case, the only thing that helped me was stubbornness and stripping things down until there was nothing left that could be wrong. Then I started adding back sections until the problem reoccurred. Case sensitive searches of the same variables pointed out the caps problem. Nothing brilliant, but things that I hadn't thought to do right away. Oh, that.... and a bunch of luck.

Bo