dovecot - Jul 2006 - Dovecot] Error appear when Update Dovecot-0.99.14-r1 to Dovecot-1.0.rc2

Hello!
Today, I tried to update Dovecot, initially everything pretended to be OK,
but after update I see dovecot.log and found this line:

"
dovecot: Jul 18 11:26:03 Error: IMAP(dario.a at telpin.com.ar): file
istream-raw-mbox.c: line 485 (istream_raw_mbox_get_body_size): assertion
failed: (rstream->mail_size != (uoff_t)-1) "

This line is repeated for many users, then I had to return to
Dovecot-0.99.14-r1.
This is my condiguration file for Dovecot-1.0.rc2:

"
base_dir = /var/run/dovecot/
protocols = pop3 pop3s imap imaps
listen = *
disable_plaintext_auth = no
shutdown_clients = yes
log_path = /var/log/dovecot.log
info_log_path = /var/log/dovecot.log
ssl_listen = *
ssl_disable = no
ssl_cert_file = /etc/ssl/dovecot/dovecot.crt ssl_key_file
/etc/ssl/dovecot/dovecot.key login_chroot = yes default_mail_env
mbox:%h:INDEX=/etc/dovecot/dovecot-indexes%h:INBOX=%h.mbox
mail_extra_groups = vmail
mail_read_mmaped = yes
mmap_disable = yes
lock_method = dotlock
valid_chroot_dirs = %h
mail_save_crlf = no
mbox_read_locks = dotlock
mbox_write_locks = dotlock
protocol imap {
}
protocol pop3 {
  pop3_uidl_format = %v%u
}
auth default {
  mechanisms = plain
  passdb sql {
    args = /etc/dovecot-mysql.conf
  }
  userdb sql {
    args = /etc/dovecot-mysql.conf
  }
  user = root
}
"

I am using NFS for Mboxes, no for INDEX Files.
Please, could somebody help me? 
Thanks.

--
Dario Ale (dario.a en telpin.com.ar)