The remote host is missing an update to gnutls13, gnutls26 announced via advisory DSA 1719-2.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201719-2

Changes in DSA-1719-1 caused GNUTLS to reject X.509v1 certificates as CA root certificates by default, as originally described in the documentation. However, it turned out that there is still significant use of historic X.509v1 CA root certificates, so this constitutes an unacceptable regression. This update reverses this part of the changes in DSA-1719-1. Note that the X.509v1 certificate format does not distinguish between server and CA certificates, which means that an X.509v1 server certificates is implicitly converted into a CA certificate when added to the trust store (which was the reason for the change in DSA-1719-1). The current stable distribution (lenny) was released with the changes in DSA-1719-1 already applied, and this update reverses the changes concerning X.509v1 CA certificates for this distribution, too. For the old stable distribution (etch), this problem has been fixed in version 1.4.4-3+etch4. For the stable distribution (lenny), this problem has been fixed in version 2.4.2-6+lenny1. We recommend that you upgrade your GNUTLS packages.