It told you exactly how to do it... edit /etc/ssh/sshd_config and set: Protocol 2
From the sshd_config man page:
Specifies the protocol versions sshd supports. The possible val-
ues are ``1'' and ``2''. Multiple versions must be comma-sepa-
rated. The default is ``2,1''. Note that the order of the pro-
tocol list does not indicate preference, because the client
selects among multiple protocol versions offered by the server.
Specifying ``2,1'' is identical to ``1,2''.
webhostinginfo - see what Chris_M said and do that and please do not PM me after I've given you enough info to do it here. Heck, even the error message should have been enough. If you have a dedicated server and it isn't managed, and the instructions to edit a file and the assumption that you'd know to restart the service afterward didn't make sense, I'd recommend finding a management company while you bone up on some of the more basic UNIX skills.
Not to be harsh, but I think I'm giving constructive criticism here that just may save you some future headaches.