I have Office Xp and Exchange 2000 SP3.
This is not an answer I'm afraid, but some further clues for someone cleverer than me to sort!
This happens to me and no-one else on my network. I thought re-installing Office XP might help - it doesn't.
If I get someone else to log on to my PC and set up their Out of Office Assistant, it works fine. It must be an Exchange 2000 issue, but I don't know where to look to find out why.
Good luck! As someone who has been nagging staff to use OOOA, it's embarrassing to have mine not working..
Regards
Andrew Boarder
Winchester
Hampshire, UK