error codes when running pg_dumpall from a perl script.

Hi,
If this was better posed in a different postgres group, please let me
know.

I'm having problems when running pg_dumpall from a perl script.

Here's the line that's executing the backup.

`pg_dumpall -o |bzip2 -z -c > $os_bkup_loc/byt_pgdump_full.bz2` or warn
"Error while running probably all OK. $! \n";

During the run the following error is reported

"Error while running probably all OK.. Illegal seek "
i.e. the error code reported by $! is "Illegal seek"

I've ran a backup manually, and there are no error messages.
When running the backup from with a perl script, (but not sending the output
through bzip2) the error still occurs, but diffing the output of that with
the output of pg_dumpall -o when ran from the command line and there's only
two minor differences (which seem to be within some objectIDs. I can post
that diff if anyone thinks it may help.

the environment variables PGUSER and PGPASSWORD are set earlier in the
script.
I've searched the archives of the mail lists, and found no references to
illegal seeks WRT running pg_dump.

Anyone got any clues ?

--
Simon Crute