I 'resolved' this by deleting all current shares in Outlook2007 and resending
the share email. It seems you can only send one invite and it has to include
all the people you want to share with.

"Jeff Cashman" wrote:

I set up a shared calendar on office online with the publish feature in
outlook2007. I sent the initial invite during the setup and it worked fine.
Now I am trying to add additional users with the right-click Share Calender
and it creates the email fine. I add receipents and click send and get the
following error: error while preparing to send sharing message. server
returned an error.

It's driving me nuts