Problems accepting changes in recurring meeting requests

[Meridith]

Hi,

When an organizer of a meeting sends updates to a meeting some of the
invitees cannont accept the change. The following error occurs:
“Property does not exist. Field you want to modify is not valid for this
type of item.â€
Both users are on Exchange and are using a standard appointment in Office
2007.
There are no custom forms being used.

Any Ideas??

thanks!