Can't retrieve email using AppleMail suddenly


I have been using my Apple Mail for 1 month now... Everything was working fine. Somehow, I cannot retrieve my emails suddenly. I can see it on the server using "Get info" but it will not download and display.

I have read in other forums to delete the "MessageUidsAlreadyDownloaded" file. It started to work again for a couple of days but it has happened again now.. Even after deleting the file again, nothing seems to work.

Please help.. I'm using Apple Mail v2.0.1 (730).