Thunderbird problem

On my Windoze box (XP Professional), Thunderbird suddenly lost all my folders in my IMAP mailbox. I've tried tweaking the profiles, editing the profiles, deleting the .msf files from the profiles, and deleting and re-creating the mailbox -- to no avail.

How can I get Thunderbird to access all my folders again? They're still on the server (it's a Linux-based IMAP server and I've got shell access).

Any and all help would be appreciated.

Update:

When I go to "subscribe" to the folders under my IMAP folder, they don't exist, even when I click "refresh".

I have tried removing and recreating my mailbox to no avail; it still comes up as if the folders don't exist when I try to "subscribe" to them.