I hope this hasn't been posted yet somewhere but I couldn't find anything.

Yesterday evening I transferred all my email from my own imap account (own domain) to googlemail via imap. I've set up the pre to use gmail via imap, update every 30min and show me the last 7 days worth of email.
But what it does in inbox is:
It shows me the newest email (only one, sometimes 2) and then it shows me a random number of very (very!) old email. Right now it has about 150 emails from a time period of 3 months in early 2005. This morning it showed me the seven oldest emails on the account from sometime in 2004.
In all other mailboxes (sent/trash/etc) it seems to work flawlessly.

Does anybody have any idea if this is a problem with googlemail, the pre, or something that I did wrong? It worked flawlessly on my old account but I really want/need to switch to googlemail.

Thanks in advance,