BUG #5977: Crash on delete

The following bug has been logged online:

Bug reference: 5977
Logged by: Anton Kuznetsov
Email address: antosha86(at)mail(dot)ru
PostgreSQL version: 8.3.1
Operating system: Linux 2.4.32
Description: Crash on delete
Details:

Server crases on delete and than automatically restarts;
Log message was:

TRAP: FailesAssertion("!(outerstartsel <= outerendsel)", File:
"costsize.c", String: 1540)
Log: Server process (PID 11785) was terminated by signal 6: Aborted;
Log: Shutting down other active server processes
Warning: Closing connection due to shutdown of other server process.
The postmaster has command this process to rollback the current transaction
and exit, because other server process exited abnormally and possibly
corrupted shared memory.
In a moment you should be able to reconnect to the database and repeat your
command.

...And so on for each process.

All server processes stoped... restarting;
Database system was interrupted; last known up at 2011-04-13 11:33:57 MSD;
Database system shutdown abnormally; automatic recovery;
REDO begin from 1/F168073C
record with zero length in 1/F27055AC
REDO end in 1/F2705580
last completed transaction transaction was at log time 2011-04-13
11:34:36.383714+04
autovacuum launcher started
database system is ready to accept connection

Delete query not appeared in log file (query log enabled)

Using hibernate 3.0 to work with database;
and Slony1-1.2.14-1.i486 to manage replication.
Delete is not working with only one table, but with all records (prevuously
added or new ones);
Things i allready try;
dump database;
create new one with same structure (and without replication);
restore only table data from dump to new database;
run "vacuum full analayze" and "reindex database";