[Dovecot] 1.0-test53 and 'Junk in start of group' messages

Hello.

I am using dovecot-1.0-test53 with Maildir mailstore, with pine 4.61 as MUA.

I have several folders which cause error messages like 'Junk in start of group' in Pine when I read them. I googled a bit for this, and found that removing the index file should do the trick, but unfortunately, it does not.

What can I do to make these annoying messages disappear ?

Thanks in advance.

-- Nicolas