Warm standby problems

Hi,

I have one PostgreSQL 8.3 machine feeding WAL files to another PostgreSQL 8.3
machine that's running in recovery mode. However, fairly often (every
few days), the standby machine breaks out of recovery mode with log messages
like:

2009-10-23 21:47:40 EDT LOG: incorrect resource manager data checksum in record at 11/4E5AA18C
2009-10-23 21:47:40 EDT LOG: redo done at 11/4E5A9A40
2009-10-23 21:47:40 EDT LOG: last completed transaction was at log time 2009-10-23 21:28:36.531005-04
2009-10-23 21:47:40 EDT LOG: restored log file "00000001000000110000004E" from archive
cp: cannot stat `/var/backups/postgres/wal/00000002.history': No such file or directory
2009-10-23 21:47:46 EDT LOG: selected new timeline ID: 2
cp: cannot stat `/var/backups/postgres/wal/00000001.history': No such file or directory
2009-10-23 21:47:52 EDT LOG: archive recovery complete
2009-10-23 21:47:55 EDT LOG: database system is ready to accept connections

I'm pretty sure the WAL is shipped correctly (it's shipped via SCP).
The only thing I can think of is that the shipping version is 8.3.7 and
the consuming version is 8.3.8. Would this be enough to cause the
"incorrect checksum" message?

Regards,

David.