Problem with windows Postgres 8.3.1 MSI binary distribution

Hello,

I have a problem with the windows Postgres 8.3.1 MSI binary
distribution. When I attempt to install postgres 8.3.1
with postgres automatically creating its own user account, the
installer complains:

"Service 'PostgreSQL Database Server 8.3'(pgsql-8.3) failed to start.
Verify that you have sufficient priveleges to start system services."

This, despite the fact that 4 postgres.exe processes are now visible
in task manager, running as the just created postgres user. I believe
that the installer creates accounts with the ability to log on as a
service, and to log on locally, so this shouldn't be a problem.
Besides, I've manually ensured that the account has these privelege in
"Local Security Settings", and the account I run
PGinstaller is an administrative account.

This is a new user account, not one from a previous postgres install.
I deleted all the older ones in the well hidden "Local Users and
Groups" dialog.

What should I do to prevent this messagebox from appearing, which
forces me to roll back the installation?

Regards,
Peter