Hi there. Had about five people on the server, we decided to try out the new OP4 coop and after downloading that map from the server it gave me this error, and likely for everyone else too as the server is now empty. Any solutions? Just thought I'd like you know, I'm not sure if this is the case for other servers.

Delete the one in your svencoop maps folder and you'll be able to reconnect. The default name of the map has a hyphen in front of the name, but I don't like maps with hyphens in there names as it screws up serverdoc's ability to restart a server after crash.