EAP-TLS authentication fails with WinXP

[ANISH NAIR]

Hi,
I am trying out hostapd with WinXP supplicant using EAP-TLS. The RADIUS
server being IAS on Windows 2000 server (domain controller). I was able to
add the client certificates. But when the WInXP supplicant tries to
authenticate, IAS reports the errors in the following sequence:
1) Event Type: Error
Description: The user "domain/username" has connected and failed to
authenticate because of the following error. The supplied message is
incomplete. The signature was not verified.

2) Event Type: Warning
Description: user "username at domain" was denied access.
Reason: This was an authentication failure because of an unknown user name
or a bad password.	

Any idea on what went wrong. I am using the hostap driver version
2002-10-12.

Thanking in advance.

Best Regards
Anish