The remote host is missing an update to bind9 announced via advisory USN-865-1.
The problem can be corrected by upgrading your system to the following package versions: Ubuntu 6.06 LTS: libdns23 1:9.3.2-2ubuntu1.9 Ubuntu 8.04 LTS: libdns36 1:9.4.2.dfsg.P2-2ubuntu0.4 Ubuntu 8.10: libdns44 1:9.5.0.dfsg.P2-1ubuntu3.4 Ubuntu 9.04: libdns46 1:9.5.1.dfsg.P2-1ubuntu0.3 Ubuntu 9.10: libdns53 1:9.6.1.dfsg.P1-3ubuntu0.2 In general, a standard system upgrade is sufficient to effect the necessary changes. https://secure1.securityspace.com/smysecure/catid.html?in=USN-865-1
Michael Sinatra discovered that Bind did not correctly validate certain records added to its cache. When DNSSEC validation is in use, a remote attacker could exploit this to spoof DNS entries and poison DNS caches. Among other things, this could lead to misdirected email and web traffic.