Unable to open this mailbox

I just set up courier-imap on my machine but I couldn't open the INBOX:

2 SELECT INBOX
2 NO Unable to open this mailbox.

I thought it would be a permission problem but the dirs are set with 700. I also read that it could be the server's date time, which didn't seem to be the case at all.. I then bumped into this thread in the Ubuntu forum to find out that I should have used maildirmake command to create the maildir, bah.

- yc