I seem to recall seeing this before: the Perl client gives the error "No disk space remaining for your account." if you don't have any galleries defined. I just tested it, and it does not do it if you have a gallery, even if you don't specify one on the command line.
It might be worthwhile adding the ~/.fotoup.conf documentation to the usage printout if you don't have one yet. I was expecting it, but only because I'd read the code.
Other than those minor issues, it's a fine piece of work. The ability to back up your photos is just wonderful (though I haven't tried it yet).
