Well from what i gather of your system. You have XP pre SP1. I know this cause the build date of your XP is 08/17/01 which is real early in the development.
I can almost bet you that installing SP1/SP2 will fix this.
Since you say you are on Dial-Up I know that this would take weeks. So here is a link where you can order SP2 right from M$
Order Windows XP Service Pack 2 on CD
From what i gather they will do this for free. I just had to input my address and there was no charge.
Other than that i found this
Check your copy of the wsock32.DLL (find it under \windows\system, right click it, and select properties to get this info) It should be dated 7-11-95, at version 4.00.950. If you have a NEWER version, then that should be ok, as long as it's a file created by Microsoft (look for MS copyright under version).
To replace your winsock.dll with Microsoft's, do this:
Go into Control Panel, and double click on the Network icon.
Click on the Add button.
Select protocol, and click the Add button.
On the left side of the window, select Microsoft.
On the right side of the window, select TCP/IP.
Now click on the OK button.
Be sure you have you Windows set-up CD/Disks ready. It's a good idea to do this when you aren't online. So to be safe, reboot your computer before you do this. Once it has installed the files, reboot your computer again.
This isn't a fix, only a suggestion. GameSpy was developed under the Microsoft's Dial-up Networking (DUN) and winsock. So the BEST solution is to manually install your own DUN, and setting up your own TCP/IP stack specific to your ISP. This isn't a overly complicated task, but it is some what involved. Which is why most ISP's have their own installation software, plus some ISP's like to tweak things to their own liking, which doesn't always guarantee compatibility with all winsock applications.
The GameSpy team doesn't have the same resources as the development team such as Netscape, or Microsoft, where they have ample resources to test their product on every single conceivable computer networking set up that may exist. We can't find ways around possible conflicts, and incompatibility issues, because we don't have the resources yet, so we rely on user feedback.
Problem is that most user feedback are just people complains that "it doesn't work, fix it please!" So without hands-on access to the problem at hand, it's hard to know the problem, let alone to find a way to fix it.
But i dont know if that will work for you. I think updating will be your best option.