I have exactly the same problem. Suddenly all emails from the inbox (OE 6 on XP) after mid 2008 vanished. Also if I send myself an email, it says 1 email in Inbox, but when I look - its not there. This can be repeated any number of times. Anybody got any ideas? - some of these emails are important!! (By the way I couldn't getanything from that link someone kindly suggested).
Thanks