The remote host is missing an update as announced via advisory SSA:2003-346-01.
lftp is a file transfer program that connects to other hosts using FTP, HTTP, and other protocols. A security problem with lftp has been corrected with the release of lftp-2.6.10. New packages are available for Slackware 8.1, 9.0, 9.1, and -current. Any sites using lftp should upgrade to the new packages.