Sorry if I'm rude, but you are wrong, terribly.
All I did is open the console, and typed these exact words:
Addfile scr_mysticrealm44.wad and then pressed the enter key, like we all do to activate a command in the console. The game then stopped running the server and took me back to the title screen. No message windows of in-game errors appeared or anything......I tried again and it happened again.
That's what happened, I did what I was supposed to, what now, answers, anyone?