you're both trying too hard. Its unlikely to be the 802.1x issue
The problem now is that he's using WEP not WPA, and in most cases XP cannot autoconfigure a WEP connection. You have to do it by hand.
This is a standard problem with WEP but rarely documented
Details here on this helpfile from Netgear
Unable to connect to network: Validation and Certificate Errors in Windows XP and Vista
note that you may still come across the issue of whether the WEP has to be "open" or "shared" - that can be changed here at the same time. If one fails, try the other