I had to reinstall COD UO after some sort of glitch in the matrix. It should be working as new, but when I try to open the program it gives me this error message right away and shuts itself down:

recursive error after: Can't use keys with a "
key: 'tdm"'
value: '<NULL>'


Any suggestions?

The reason a reinstall didn't fix is because d/l maps & mods were not deleted when you uninstalled the game.
You have something in your /uo directory causing this problem.
Remove everything from the /uo directory that isn't stock to the game.
If you have a question about if a cetain file should be removed or not, let us know & someone will help you.

I'm at work at the moment so I can't list all the stock files but here are the ones I remember
pakuo00.pk3
pakuo01.pk3
pakuo02.pk3
pakuo03.pk3
pakuo04.pk3
pakuo05.pk3
pakuo06.pk3
pakuo07.pk3
Plus there are several .Pk3 files which have localized english in their name, be sure to keep those as they are stock files.

Just try removing all non-stock pk3 files until the problem is solved.

There is a small chance it's caused by something in your coduo_mp.cfg.
You can delete this file, and let the game creat a new one.