Mpd+ Freeradius

[..::--:Carlos:::Ariel:::Canta:--::..]

Hello, i configure a Mpd server (for vpn server)  with freeradius 
authentication,i get the next error when i connect:

[pptp0] RADIUS: RadiusSendRequest: rad_send_request failed No valid RADIUS 
responses received
  Peer name: "carlos"
  Can't get credentials for "carlos"
[pptp0] CHAP: sending FAILURE
[pptp0] LCP: authorization failed
[pptp0] device: CLOSE event in state UP

Someone can help me

-- 
Carlos Ariel Canta
::BSD::Admin::
Redynet S.R.L