Attribute "User-Password" is required for authentication

[Cody Jarrett]

I found a few topics on this issue but nothing quite informative enough. 
I'm trying to get freeradius auth working with pam and peap. When I test 
my config with radtest, I get Access-accept. When I use a windows XP 
supplicant with a 3com access point, I get:

rlm_pam: Attribute "User-Password" is required for authentication.
modcall[authenticate]: module "pam" returns invalid for request 4
modcall: leaving group authenticate (returns invalid) for request 4
auth: Failed to validate the user.

Is the 3com not sending User-Password attributes in the packets, or is 
something else wrong?