We have one user who when trying to change their password is getting
the following error:

The User name or old password is incorrect. Letters in passwords must
be typed using the correct case.

Domain Controllers are Win2k8R2 and we are a Win2k8 functional domain
level.

Workstation is Windows XP SP3.

I have already seen Microsoft KB articles 896166 and 256287

This happens to the user no matter what machine in the domain he tries
to change his password from. I can change mine just fine from his
machine. Any ideas?

Thank you in advance