It appears our IT Dept. has blocked the use Limewire. How can I reverse this. I have Admin rights to the server.

Ban the IP dept. lol
It depends how they have done this, if it is via blocking ports or using a special program or bandwidth detector & blocker / shaper.

I'd suggest trying different ports. Ports such as between 49152 - 65535.

A proxy is another option but I suspect difficult on such a network with lots of security to block activity that isn't authorised.

Someone else may have more ideas.