ICal Crashes When Sending Meeting Invite/Reply

Question

iCal is otherwise functioning normally, but when you send out the meeting invite to the attendees, iCal immediatedly quits. The same happens when you attempt to confirm or deny a meeting invite from another person. The usual iCal fixes I have used in the past don't seem to be working.
I have:
Reset the iSync History
Blown out the Application Support data
iCal Plist
dumped launchservices.plist
Tested with another local user- it did work (as usual)
1.67Ghz 17" AlBook   Mac OS X (10.4.3)  

Answer 1

Starting the problem trace at the beginning, the
invitations are being sent from people in your
Address Book, correct? I ask this because a client of
mine was getting messages from an alternate address
(billb@ and not bill@) and these were getting skipped
(not sent to iCal) because billb@ was not a
registered Address Book entry.
The fast way to tell is look at the mail and see if
there is a green dot to the left of the message.
I'm still not to the point of recommending an iCal
reinstall, though. There are a few other things that
it could be.
So, the sender of the message is in my address book as "[email protected]".
I also have the Exchange LDAP store configured in Address Book, and the sender is resolvable there as "[email protected]".
The message is sent from their machine via Outlook and Exchange. On the invitation, the senders address appears as shown in LDAP.
The recipient (myself) is as their client resolved from the Exchange server, so "[email protected]". The first entry on my "me" card is "[email protected]".
I see no "green dot" next to any email.
At the moment, though, automatic transfer of the invitation is less important than elimination of the Address Book crashes. However, I do appreciate the help -- any more ideas?
--phil