The remote host is missing an update as announced via advisory SSA:2004-223-01.

https://secure1.securityspace.com/smysecure/catid.html?in=SSA:2004-223-01

New Mozilla packages are available for Slackware 9.1, 10.0, and -current to fix a number of security issues. Slackware 10.0 and -current were upgraded to Mozilla 1.7.2, and Slackware 9.1 was upgraded to Mozilla 1.4.3. As usual, new versions of Mozilla require new versions of things that link with the Mozilla libraries, so for Slackware 10.0 and -current new versions of epiphany, galeon, gaim, and mozilla-plugins have also been provided. There don't appear to be epiphany and galeon versions that are compatible with Mozilla 1.4.3 and the GNOME in Slackware 9.1, so these are not provided and Epiphany and Galeon will be broken on Slackware 9.1 if the new Mozilla package is installed. Furthermore, earlier versions of Mozilla (such as the 1.3 series) were not fixed upstream, so versions of Slackware earlier than 9.1 will remain vulnerable to these browser issues. If you still use Slackware 9.0 or earlier, you may want to consider removing Mozilla or upgrading to a newer version. For more details on the outsanding problems, please visit the referenced security advisory.