I receive the message, "Invalid updates configuration file. The first line of the .INI file should be ";aiu;".
I checked a variety of possible problems and found that when I originally put the information into AI's updater page I forgot to put my own Web site info in (eg. http://www.example.com/updater/updates.txt was in the INI file instead of my own Website URL).
I hope that helps someone else... check that if the "real" solutions still don't work