No, it's on {coop "1" }though
I went through the list of commands skidz said not to put in the server.cfg and I took all of them out and still no luck.
I just reinstalled and it works again. I don't know what I did, but I'll figure it out possibly.
"For though I fly through the shadow of the Valley of Death, I will fear no evil, for I am at 70,000 feet and climbing"
The 'coop' cvar has nothing to do with the 'deathmatch' cvar. I have no idea what the 'deathmatch' cvar is for, but as long as it is set to 0, mapchanges will always fail, and this happens on other games (CS:S, HL2DM) as well. Interestingly, despite defaulting to 0, it's still 1 when you launch the server without server.cfg.