named "not enough free resources" error

[Ross Finlayson]

May 15 16:05:30 ns named[398]: client 66.80.0.9#1075: error sending 
response: not enough free resources
May 15 16:05:38 ns last message repeated 2 times
May 15 16:05:39 ns named[398]: client 66.80.0.9#1096: error sending 
response: not enough free resources
May 15 16:05:47 ns last message repeated 2 times
May 15 16:05:56 ns named[398]: client 66.80.0.9#1075: error sending 
response: not enough free resources
May 15 16:05:58 ns named[398]: client 66.80.0.9#1075: error sending 
response: not enough free resources
May 15 16:05:58 ns named[398]: client 66.80.0.9#1096: error sending 
response: not enough free resources

%netstat -m
231/294/525 mbufs in use (current/cache/total)
106/156/262/8896 mbuf clusters in use (current/cache/total/max)
106/150 mbuf+clusters out of packet secondary zone in use (current/cache)
0/0/0/0 4k (page size) jumbo clusters in use (current/cache/total/max)
0/0/0/0 9k jumbo clusters in use (current/cache/total/max)
0/0/0/0 16k jumbo clusters in use (current/cache/total/max)
269K/385K/655K bytes allocated to network (current/cache/total)
0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/4/2480 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
0 requests for I/O initiated by sendfile
0 calls to protocol drain routines

%cat /etc/motd
FreeBSD 6.1-STABLE (GENERIC) #3: Tue May  9 19:36:33 PDT 2006

Any ideas?  (Is this a known issue that has been fixed since May 
9th?)  Also, FWIW, the client to named was using the "ath0" interface.

         Ross.