pg_dump problems

Hi !

We have an old web service with a pgsql database (in Suse Linux). This
database created by another programmer who no accessible now.

We want to dump this database to get data from it. But I have no passwords.

I do many things, but I cannot create dump from this database.
I know the name of database (inventory), and from zope I see this
connection parameters: "dbname=inventory users=zope". And from zope that
is working good.

When I try to make pg_dump:

pg_dump -s -v -U zope -W inventory >/invdump

it prompt for pwd, and I get auth. error.

When I try to create dump with def. user:
pg_dump -s -v -W inventory >/invdump

It is show error that "root user doesn't exists".

So: how to I dump this database ? Or how to I transfer it to a Windows
machine to make dump on it ?

Is anybody have a solution ?

Thanks for advance: dd