Zaroff
Like Skuzzy said it could be a built in AV program in the firewall limiting your ability to connect to the game. Also they may be a limit to the amount of bandwith as to which you are able to access. My place of employment has free wifi but it limits which website I can access. For example I cannot access wwe.com but I can access "other" sites??? What you might need to do is contact the IT and let him know what is going on and see if he or she can give you a bypass for the game and go from there, but be advised you may get poor performance from the game. The IT may also have to put in the game IP as a exception in the firewall.
Go see them and go from there.
LawnDart