pg_restore -d password athentication failed

Hi,
I are trying to upgrade from Postgresql v7.3 Cygwin environment to 8.0.1
on a plain Windows environment. So, far, I can get most of the data
transferred, but I cannot get the large objects. Perusing the net, I got
a hint that I must use the -d dbname with the pg_restore utility.
Unfortunately, I keep getting the error message:

pg_restore: [archiver (db)] connection to database "test3" failed:
FATAL: password authentication failed for user "admin_user"

The "test3" database can be accessed with admin_user with no problems
using psql.

What am I doing wrong?

Kristina