Spawning a service on a random port that lets unauthenticated users write arbitrary files to your system is a very bad idea. ;-)
If you have shell access via SSH, why not just use SFTP? Presumably it's configured as well.
For a quick, one-time job, it works very well, and you don't have to bother configuring SSH/FTP for it :). Of course, one could build a lot on top of DRb, I just wanted to show how easy it would be :)