[Dovecot] Error from mobile client (Palm Pre)

Where I used to be able to access the server without incident, I can no longer receive mail on the mobile device. I'm seeing this in the server log:

Nov 27 23:45:05 bubba dovecot: imap-login: Login: user=<dmiller@amfes.com>, method=PLAIN, rip=173.117.196.198, lip=192.168.0.72, mpid=17422, TLS Nov 27 23:45:07 bubba dovecot: imap(dmiller@amfes.com): Error: FETCH [1.2] for mailbox INBOX UID 10652 got too little data: 0 vs 23553 Nov 27 23:45:07 bubba dovecot: imap(dmiller@amfes.com): Error: Corrupted index cache file /var/mail/amfes.com/dmiller/mdbox/mailboxes/INBOX/dbox-Mails/dovecot.index.cache: Broken MIME parts for mail UID 10652 Nov 27 23:45:07 bubba dovecot: imap(dmiller@amfes.com): Disconnected: FETCH failed bytes=88/4202

I HAVE made some tweaks to config - primarily adding plugins I never used before. These now include zlib and imap_zlib (I've tried removing imap_zlib - no change).

Daniel