Thanks for the "last update" info. But your first recommendation is wrong, alas. Imagine that you have a bluesubaru gmail account. And then I come along and buy the domain "n800.net" through google. Then I create a user "bluesubaru@n800.net," which I would be able to do. If google didn't require that my user use "bluesubaru@n800.net" as the userid, google wouldn't know which bluesubaru was trying to log in. So google quite smartly requires adding the domain to the user id for mcalendar-like purposes.

Plus it worked with my full domain for the first few days. And then started going haywire thereafter. My guess is also that the other user here who is experiencing the same problem has a standard google account, and not a google apps account.