Unable to delete recurring appointment

Hi, I get this message on the server when I try to delete old appointments in a users calendar:
Calendaring agent failed in message save notification with error 0x8007000e on

Source:EXCDO, EventID:8199

I have Exchange 2000 sp3 and the user has XPsp1 and Office XP (Swedish). I have tried to run outlook /cleanfreebusy and outlook /cleanreminders but nothing works!