Yes, I can publish directly via ftp from ical, but apparently can't subscribe to it afterwards using ical. Poitinng to the ics file on the server, I get this message when ical downloads the file:

Data downloaded from http://mydomain.org/ical/Test.ics is not valid.

Any idea why?

I have the same problem. When I logged into my server I noticed the .ics file that was published by ical is zero kb. I think iCal is publishing a blank file.

I am on my way to the Apple Genius bar to get a better answer.

I spent some time at the genius bar yesterday. None of the geniuses used the publish feature in iCal, but after some research they concluded FTP is NOT supported at this time.

The private server option is for a private webdav server.

I reported the success dialog that appears after "publishiing" to an ftp server as a bug.