BUG #1631: pg_autovacuum fails when creating as a windows service

The following bug has been logged online:

Bug reference: 1631
Logged by: Marc Soleda
Email address: msoleda2001(at)yahoo(dot)es
PostgreSQL version: 8.0.1
Operating system: WinXP SP2
Description: pg_autovacuum fails when creating as a windows service
Details:

I'm installing pg_autovacuum as a windows service. The windows user account
used is a local one and it has admin privileges:

pg_autovacuum -I -N winuser -W pwdwinuser -U pguser -P pwdpguser

and I get:

ERROR: The account name is invalid or does not exist, or the password is
invalid for the account name specified.

I've tried with different admin users but the answer is always the same.

Any ideas?

If I execute pg_autovacuum as standalone, all works fine.