The remote host is missing an update as announced via advisory SSA:2005-251-04.
A new php5 package is available for Slackware 10.1 in /testing to fix security issues. PHP has been relinked with the shared PCRE library to fix an overflow issue with PHP's builtin PRCE code, and PEAR::XMLRPC has been upgraded to version 1.4.0 which eliminates the eval() function. The eval() function is believed to be insecure as implemented, and would be difficult to secure. Note that this new package now requires that the PCRE package be installed, so be sure to get the new package from the patches/packages/ directory if you don't already have it.