I'm wondering if somehow the problem is related to the fact that you're using a web browser instead of a bonafide FTP client like SmartFTP or CuteFTP. From my experience, using an actual FTP client has never posed problems for me.
You could put a password on the ibay in question, which would then prompt for that password whenever that ibay is accessed. (Hint: the username is the same as the ibay name, the password is whatever you specified.) Set public access as "Entire Internet (password required)" in the ibay config page in server-manager. One caveat: the username/password combination is the same for all users, so you won't be able to use this method to restrict content access like you would if your clients were accessing via a FTP client like those mentioned above.
Doing this would also mean you'd use the http protocol instead of the ftp protocol in your browser.