PANIC: hash table "LOCK" hash corrupted

Hello,

I'm playing with postgres in OpenVZ. When I migrate my machine with
the database from one host to another I get following errors:

2009-10-04 20:20:43 CEST PANIC:  hash table "LOCK hash" corrupted
2009-10-04 20:20:43 CEST STATEMENT:  begin
2009-10-04 20:20:43 CEST @ LOG:  server process (PID 14554) was
2009-10-04 20:20:43 CEST @ LOG:  terminating any other active server processes

What does this mean?

Thanks,
  Gerhard