[Dovecot] Corrupt Message?

[Daniel Watts]

Dear List,

Am accessing dovecot imap through squirrelmail.
Squirrelmail paginates the message list into pages.

All works fine except for the page one particular email is in. When I 
try to open that page (or in fact click 'show all') the server returns:

ERROR: Bad or malformed request.
Query: FETCH 549,551,555:557,563,565,567:569 (FLAGS UID RFC822.SIZE 
INTERNALDATE BODY.PEEK[HEADER.FIELDS (Date To Cc From Subject X-Priority 
Importance Priority Content-Type)])
Server responded: No mailbox selected.

Could you possibly let me know what I should do and also how I can find 
the guilty mail file from that error? Can I just delete the email? Or is 
there a nice script to repair a dovecot maildir?

Many thanks for your advice,
Daniel

-- 
Squirrelmail Stable 1.4.8
PHP 5.x Hardened with Eaccelerator
Apache 2.x
Imapproxy over Dovecot/Maildir
all running on Gentoo Linux
for ~5,000 users.