[Dovecot] file index-mail-headers.c: line 408 (index_mail_get_header): assertion failed: (ret != 0)

[Dmitry Khrustalev]

FreeBSD 4.10-RELEASE, dovecot-1.0-test29 crashes on sort and thread 
commands:

Jul 25 15:12:08 owl dovecot: imap-login: Login: dima [81.19.64.101]
Jul 25 15:12:26 owl dovecot: IMAP(dima): file index-mail-headers.c: line 
408 (index_mail_get_header): assertion failed: (ret != 0)
Jul 25 15:12:26 owl dovecot: child 20384 (imap) killed with signal 6

(gdb) bt
#0  0x281e0fc4 in kill () from /usr/lib/libc.so.4
#1  0x2822293e in abort () from /usr/lib/libc.so.4
#2  0x8086c73 in i_internal_panic_handler (
     fmt=0x8095720 "file %s: line %d (%s): assertion failed: (%s)",
     args=0xbfbff8cc "\tW\t\b\230\001") at failures.c:374
#3  0x8086827 in i_panic (
     format=0x8095720 "file %s: line %d (%s): assertion failed: (%s)")
     at failures.c:173
#4  0x806d0f9 in index_mail_get_header (_mail=0x80bf41c,
     field=0x80955ce "Date") at index-mail-headers.c:408
#5  0x806b8fd in index_mail_get_date (_mail=0x80bf41c, timezone=0x0)
     at index-mail.c:218
#6  0x8059b1c in mail_sort_input (ctx=0x80a1150, mail=0x80bf41c)
     at imap-sort.c:420
#7  0x80596ae in imap_sort (client=0x80ad180, charset=0x80b1180 
"US-ASCII",
     args=0x80c8010, sort_program=0x80a10d0) at imap-sort.c:252
#8  0x8054ec8 in cmd_sort (client=0x80ad180) at cmd-sort.c:123
#9  0x80560ae in client_handle_input (client=0x80ad180) at client.c:318
#10 0x805614d in _client_input (context=0x80ad180) at client.c:354
#11 0x808a852 in io_loop_handler_run (ioloop=0x80ab040) at 
ioloop-poll.c:193
#12 0x808a245 in io_loop_run (ioloop=0x80ab040) at ioloop.c:248
#13 0x805bc5b in main (argc=1, argv=0xbfbffbb0, envp=0xbfbffbb8) at 
main.c:217
(gdb)