Access-Accept with invalid signature

[Norbert Wegener]

I want to use mysql with freeradius and a default entry in the users file.
Testing with radtest I get an Access-Accept which is ok.
But there is an additional information, which irritates me and I have no
idea, what it means. 
In case of an incorrect shared secret - as far as I know - no
Access-Accept would have been sent.

suse:/home/norbert # radtest nw123 xx localhost 0 1812 maxen
Sending Access-Request of id 32 to 127.0.0.1 port 1812
        User-Name = "nw123"
        User-Password = "xx"
        NAS-IP-Address = 255.255.255.255
        NAS-Port = 0
        Framed-Protocol = PPP
rad_recv: Access-Accept packet from host 127.0.0.1:1812, id=32, length=20
rad_decode: Received Access-Accept packet from client 127.0.0.1 port
1812 with invalid signature (err=2)!  (Shared secret is incorrect.)


The output of radiusd -AX does not show anything strange to me and can
be found at: http://www.wegener-net.de/fr/typescript

So, is the last message important or can it be ignored?
Thanks
Norbert Wegener