The remote host is missing an update to iptables announced via advisory DSA 580-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20580-1

Faheem Mitha noticed that the iptables command, an administration tool for IPv4 packet filtering and NAT, did not always load the required modules on it own as it was supposed to. This could lead to firewall rules not being loaded on system startup. This caused a failure in connection with rules provided by lokkit at least. For the stable distribution (woody) this problem has been fixed in version 1.2.6a-5.0woody2. For the unstable distribution (sid) this problem has been fixed in version 1.2.11-4. We recommend that you upgrade your iptables package.