I reported it as a false positive to Norton.
I restored the program from my nightly backup, and Norton immediately removed it again when I tried to run it. Now it is telling me I need to restart my computer to continue the removal of security risks.
I restored MC from my backup and renamed it to multicommander2.exe and was able to run it that way. Upon running, MC detected it was out of date and wanted to do an update. The update would not run since it could not find multicommander.exe. So I restored multicommander.exe from backup and restarted multicommander2.exe again and was finally able to get MC running again.
I changed the Norton AV settings to not automatically remove threats, so I think I will be OK now.
Hope this helps anyone else who runs into this problem.