|"cant change settings on my pc as it is controlled by It guys!"|
There is a good chance they have disabled netsend. Also when you say "It is an XP thing" do you mean that the target machine is not running xp? I remember reading that vista ships with netsend disabled by default, but I can't verify this. Win9x use don't have net send at all, I think they use a different method/command.
As for the msg command it can apparently be used over a network but I could never get it to work.... I believe it is reliant on the "terminal services" service.