Not really sure what's going wrong there - as long as you're playing with the latest version available (won't be able to go online otherwise after recent server change), game should be downloading missing mods automatically after you join the room.
Did /dl command work, or did it fail as well? If it didn't work, you probably don't have writing permissions on your Toribash folder - make sure it isn't set to readonly and that the account you're logged in with in your system has write privileges.