pg_dumpall error

Hi there, I hope that you can help

I am getting the following error message when i run the pg_dumpall
command

pg_dump: SQL command failed
pg_dump: Error message from server: ERROR:  relation
"esales.invoiceline" does not exist
pg_dump: The command was: LOCK TABLE esales.invoiceline IN ACCESS
SHARE MODE
pg_dumpall: pg_dump failed on database "hermes", exiting

The esales.invoiceline table is there are can be accessed.  We do run
overnight updates to this table and i was wondering if the updates are
conflicting with backup processs ?

We are running PostgreSQL 8.1.3 and the pg_dumpall command is

pg_dumpall -s --disable_triggers -h $CURRENT_HOST -U USER_AUTH >
schema.sql

Any help would be really appriceated.

Thanks
Fran