AS3: Problems downloading from an ftp site using FileReference

I’m using FileReference to download a file when the user clicks a button. My button works beautifully for all files on our http site, but for files on our ftp site, it fails and throws “Error #2039: Invalid remote URL protocol. The remote URL protocol must by HTTP or HTTPS.”

All the documentation I’ve found indicates that ftp is not allowed for uploads, but is fine for downloads. The ftp server I’m pulling files from does not require any kind of log-in. Is the documentation wrong? Am I screwed? Or is there a workaround? Any help would be much appreciated.