Shared calendar gone haywire!

[Leslie]

Every few days, my shared calendar attempts to send out
208 calendar updates. At first I just deleted all the
messages from the outbox. When it happened again, I let
them go through - my ISP will only except 24 outgoing
emails at a time, so I have to OK-click all the error
messages for the ones that don't get sent each time,
until all 208 are safely on their way.

A nuisance! Any suggestions?

Thanks,
- Leslie