The remote host is missing an update to nss announced via advisory DSA 2203-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202203-1

This update for the Network Security Service libraries marks several fraudulent HTTPS certificates as unstrusted. For the oldstable distribution (lenny), this problem has been fixed in version 3.12.3.1-0lenny4. For the stable distribution (squeeze), this problem has been fixed in version 3.12.8-1+squeeze1. For the unstable distribution (sid), this problem has been fixed in version 3.12.9.with.ckbi.1.82-1. We recommend that you upgrade your nss packages.