bind/dns problems

[Nostradamus]

I´ve got a problem getting my backup files from master-dns.
This is how named.conf is configured on slave.dns.whatever:

zone "master.dns.whatever" {
type slave;
file "bak.master.dns.whatever";
masters {
172.24.50.8;
};
};

and this is the error message that appears in var/adm/messages when I restart named.

Oct 1 15:52:50 slave.dns.whatever named-xfer[13814]: [172.24.50.8] not authoritative for master.dns.whatever., SOA query got rcode 0, aa 0, ancount 1, aucount 0

the bak.master.dns.whatever never appears on slave.dns.whatever
Why is that?

please ask if you need more info. /Sören