dovecot - Mar 2009 - Sieve - Backtrace after deliver(brabax): Panic: file sieve-cmu.c: line 264 (part_save): assertion failed: (buf->used - 1 == part->body_size.physical_size)

Hello,

It's my first mailserver I set up. Thanks to everybody who contributes to 
dovecot. Dovecot works great for me! One thing I want to get rid off is this 
traceback error using dovecot with sieve. Somebody can help on this?

System: Ubuntu server 8.10
dovecot --version
1.1.4
I filter for keywords in mail body with sieve.
Mail is stored at lokal harddrive.

I already deleted dovecot.index.cache - no success.

Here is what logs say:

sudo dovecot -n
# 1.1.4: /etc/dovecot/dovecot.conf
log_timestamp: %Y-%m-%d %H:%M:%S
login_dir: /var/run/dovecot/login
login_executable: /usr/lib/dovecot/imap-login
mail_privileged_group: mail
mail_location: maildir:~/Maildir
auth default:
  mechanisms: plain login
  passdb:
    driver: pam
  userdb:
    driver: passwd
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/auth-client
      mode: 432
      user: postfix
      group: postfix

/var/syslog
Mar 10 22:19:01 aquarius /USR/SBIN/CRON[23838]: (root) CMD 
(/etc/webmin/fetchmail/check.pl --owner --errors)

Mar 10 22:19:04 aquarius deliver(brabax): Panic: file sieve-cmu.c: line 264 
(part_save): assertion failed: (buf->used - 1 ==
part-
>body_size.physical_size)
Mar 10 22:19:04 aquarius deliver(brabax): Raw backtrace: 
/usr/lib/dovecot/deliver [0xb8068e01] -> 
/usr/lib/dovecot/deliver(i_syslog_fatal_handler+0x38) [0xb8068ee8] -> 
/usr/lib/dovecot/deliver [0xb8068695] -> 
/usr/lib/dovecot/modules/lda/lib90_cmusieve_plugin.so [0xb7e394b6] -> 
/usr/lib/dovecot/modules/lda/lib90_cmusieve_plugin.so [0xb7e3ac24] -> 
/usr/lib/dovecot/modules/lda/lib90_cmusieve_plugin.so [0xb7e43b34] -> 
/usr/lib/dovecot/modules/lda/lib90_cmusieve_plugin.so [0xb7e43e13] -> 
/usr/lib/dovecot/modules/lda/lib90_cmusieve_plugin.so(sieve_eval_bc+0x47e) 
[0xb7e4533e] -> 
/usr/lib/dovecot/modules/lda/lib90_cmusieve_plugin.so(sieve_execute_bytecode+0x125)
[0xb7e4b4d5] -> 
/usr/lib/dovecot/modules/lda/lib90_cmusieve_plugin.so(cmu_sieve_run+0x325) 
[0xb7e3a785] -> /usr/lib/dovecot/modules/lda/lib90_cmusieve_plugin.so 
[0xb7e38456] -> /usr/lib/dovecot/deliver(main+0x1229) [0xb7ff2c39] -> 
/lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe5) [0xb7e6b685] -> 
/usr/lib/dovecot/deliver [0xb7ff0531]