The remote host is missing an update as announced via advisory SSA:2007-205-02.

https://secure1.securityspace.com/smysecure/catid.html?in=SSA:2007-205-02

New SeaMonkey packages are available for Slackware 11.0 and 12.0 to fix possible security issues. While this update has been reported to MozillaZine to 'fix several security issues', details are not yet available. Presumably the issues are similar to the ones that were recently addressed in Firefox and Thunderbird. More details about the issues may (eventually) be found here: http://www.mozilla.org/projects/security/known-vulnerabilities.html#seamonkey