lame server problem in named, named shutting down

Hi,

I am using Redhat 7.1 with bind-9.1.3-4
I am using this server as primary dns, and i have secondary dns too.

i am getting this sort of entries in my /var/log/messages

Jan 31 12:17:10 ns1 named[27305]: lame server on 'genie.com' (in
'genie.com'?): 198.4.75.100#53
Jan 31 12:17:10 ns1 named[27305]: lame server on 'genie.com' (in
'genie.com'?): 169.132.133.1#53
Jan 31 12:17:13 ns1 named[27305]: lame server on 'genie.com' (in
'genie.com'?): 169.132.133.1#53

Jan 31 12:26:13 ns1 named[27305]: lame server on 'internetconnect.net'
(in 'internetconnect.NET'?): 66.246.90.10#53
Jan 31 12:26:15 ns1 named[27305]: lame server on 'internetconnect.net'
(in 'internetconnect.NET'?): 66.246.90.100#53

and i am getting 100s of these, i tried to block those ip's in my
firewall, but these ip's are changing constantly, so i am not able to
block them now,

after i get these messages, sometimes my dns is stopping


Jan 31 02:19:55 ns1 named[13809]: message.c:782: REQUIRE(*rdataset ==
((void *)0)) failed
Jan 31 02:19:55 ns1 named[13809]: exiting (due to assertion failure)

i get the above line?

what should i do to stop this name server resolving??

in my /etc/named.conf

i have
zone "." {
type hint;
file "named.ca";
};

zone "0.0.127.in-addr.arpa" {
type master;
file "named.local";
};

zone "1.16.172.in-addr.arpa" {
type master;
file "1.16.172";
};

and remaining are zones which are on my server.