The remote host is missing an update to gnocatan announced via advisory DSA 315-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20315-1

Bas Wijnen discovered that the gnocatan server is vulnerable to several buffer overflows which could be exploited to execute arbitrary code on the server system For the stable distribution (woody), this problem has been fixed in version 0.6.1-5woody2. The old stable distribution (potato) does not contain a gnocatan package. For the unstable distribution (sid) this problem will be fixed soon. We recommend that you update your gnocatan package.