Windows XP connection to Mac-generated network for web sharing

I'm debugging an issue with IE on a web site I'm building (surprise, surprise).

Rather than running across the hall to a desktop Windows machine every time I post a new change to the test server, I borrowed a Windows laptop to sit on my desk next to me.

First problem: My work network is locked down to the point that a machine logged in to the campus-wide wireless network can't get to our test server. OK, I say to myself, I'll take a simple copy of what I'm working on, put it on my local machine and serve it out over a personal wireless network using web sharing.

Great in theory, but being troublesome in practice. Web sharing is working fine, I can access my local machine from other networked machines within my subnet. Wireless is working fine, the XP laptop connects to the network [machinename] like a champ. I must be missing something, however, because I can't find the shared web site through the wireless on the XP laptop.

I've tried accessing by machine name, by IP address, by [machinename].local ... all with no success.

And so I appeal to you, kind MacRumors Forum reader, for clever ideas or pointers to the obvious that I've missed.