Unable to access http://source-folder/SUBFOLDER

On Vista RTM, default settings, VPN works fine. I can access email and
folders on the server. But, a URL like http://source-folder/SUBFOLDER fails
completely in IE7 with the message: "Internet Explorer cannot display the
webpage."

Wierdly, the URL takes me to a (poorly translated) Chinese site
(http://www.codeidea.com/) in FireFox.

Colleagues (& me when formerly on XP) have no problem with the URL.

I'm in a hotel, but two different hotels and one small business system
(behind a simple router) have the same problem, so I don't think this is my
provider's problem. (I wasn't able to test this before going on the road...)
The hotel ISP gave me a semi-permanent IP and opened up all ports for me.

Any suggestions on where to dig? I'm going to be on the road for two weeks
and need this access NOW!

Thanks for any help.