The remote host is missing an update as announced via advisory SSA:2003-337-01.
Rsync is a file transfer client and server. A security problem which may lead to unauthorized machine access or code execution has been fixed by upgrading to rsync-2.5.7. This problem only affects machines running rsync in daemon mode, and is easier to exploit if the non-default option 'use chroot = no' is used in the /etc/rsyncd.conf config file. Any sites running an rsync server should upgrade immediately. For complete information, see the rsync home page: http://rsync.samba.org