The remote host is missing an update to zaptel announced via advisory DSA 1699-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201699-1

An array index error in zaptel, a set of drivers for telephony hardware, could allow users to crash the system or escalate their privileges by overwriting kernel memory (CVE-2008-5396). For the stable distribution (etch), this problem has been fixed in version 1.2.11.dfsg-1+etch1. For the unstable distribution (sid) and the testing distribution (lenny), this problem has been fixed in version 1.4.11~dfsg-3. We recommend that you upgrade your zaptel package.