[Dovecot] after updating to dovecot 1.0a series, nokia 9500 communicator crashes while checking imap mailboxes?

After updating from Dovecot 0.99.x series to Dovecot 1.0A, Nokia 9500 communicator crashes frequently while checking imap mailboxes over wlan?

Any ideas? Any people with same problem? Looks like it dovecot relates since, it works with 0.99.x series.

-- Eero