try going onto your gmod main menu when not not on a server, put this command in consoleIn console then restarting your game and try join the server.
If this doesn't work and nobody helps you by the time I am home I will try help you.

try going onto your gmod main menu when not not on a server, put this command in console [code]menu_cleanupgmas[/code] In console then restarting your game and try join the server. If this doesn't work and nobody helps you by the time I am home I will try help you.