Acct-Terminate-Cause = NAS-Error

["Flavio Silvestrone" <drascii@gmail.com>]

Hello list,
i have a problem with freeradius and an Access Point configured as NAS.
I'm using freeradius version 1.1.6.
I suppose that the problem is about this message:
Acct-Status-Type = Stop
        Acct-Terminate-Cause = NAS-Error

Here the complite log:

Thu Jul  5 10:57:26 2007
        Service-Type = Framed-User
        Framed-Protocol = PPP
        NAS-Port = 401
        NAS-Port-Type = Ethernet
        User-Name = "massi"
        Calling-Station-Id = "00:15:D6:24:32:52"
        Called-Station-Id = "internet-test-2.4GH"
        NAS-Port-Id = "wlan1"
        Acct-Session-Id = "81f0005c"
        Framed-IP-Address = 10.1.1.7
        Framed-IP-Netmask = 255.255.255.0
        Acct-Authentic = RADIUS
        Acct-Status-Type = Start
        NAS-Identifier = "FlyBoost"
        NAS-IP-Address = 192.168.10.36
        Acct-Delay-Time = 0
        Client-IP-Address = 192.168.10.36
        Acct-Unique-Session-Id = "e4880271975e52f1"
        Timestamp = 1183625846

Thu Jul  5 10:57:26 2007
        Service-Type = Framed-User
        Framed-Protocol = PPP
        NAS-Port = 401
        NAS-Port-Type = Ethernet
        User-Name = "massi"
        Calling-Station-Id = "00:15:D6:24:32:52"
        Called-Station-Id = "internet-test-2.4GH"
        NAS-Port-Id = "wlan1"
        Acct-Session-Id = "81f0005c"
        Framed-IP-Address = 10.1.1.7
        Framed-IP-Netmask = 255.255.255.0
        Acct-Authentic = RADIUS
        Acct-Session-Time = 0
        Acct-Input-Octets = 56
        Acct-Input-Gigawords = 0
        Acct-Input-Packets = 5
        Acct-Output-Octets = 50
        Acct-Output-Gigawords = 0
        Acct-Output-Packets = 5
        Acct-Status-Type = Stop
        Acct-Terminate-Cause = NAS-Error
        NAS-Identifier = "FlyBoost"
        NAS-IP-Address = 192.168.10.36
        Acct-Delay-Time = 0
        Client-IP-Address = 192.168.10.36
        Acct-Unique-Session-Id = "e4880271975e52f1"
        Timestamp = 1183625846

Any idea ?
Thank's
Flavio