[Dovecot] Debugging msync() failed errors

[Doug Luce]

>From today's maillog:

maillog:Dec 28 09:29:40 aurora dovecot: IMAP(doug): msync() failed with index file /home/doug/Maildir/.projects.job591/dovecot.index: Invalid argument
maillog:Dec 28 09:30:21 aurora dovecot: IMAP(doug): msync() failed with index file /home/doug/Maildir/dovecot.index: Invalid argument
maillog:Dec 28 09:30:22 aurora dovecot: IMAP(doug): msync() failed with index file /home/doug/Maildir/dovecot.index: Invalid argument
maillog:Dec 28 09:30:28 aurora dovecot: IMAP(doug): msync() failed with index file /home/doug/Maildir/dovecot.index: Invalid argument
maillog:Dec 28 09:44:46 aurora dovecot: IMAP(doug): msync() failed with index file /home/doug/Maildir/.projects.job591/dovecot.index: Invalid argument
maillog:Dec 28 09:44:47 aurora dovecot: IMAP(doug): msync() failed with index file /home/doug/Maildir/dovecot.index: Invalid argument
maillog:Dec 28 09:49:10 aurora dovecot: IMAP(doug): msync() failed with index file /home/doug/Maildir/dovecot.index: Invalid argument

Can anyone slip me some advice on how to properly go about debugging
this problem?  Is there a way to check the .index file?  Can anyone
make an educated guess as to what section of code is the likely
culprit?

Thanks,

Doug