Installing 8.0.3 on Windows 2000 Server?

I have successfully installed PostgreSQL 8.0.3 using the WIndows install
package on Windows XP Professional, but I can't seem to make it work on
Windows 2000 Server. There's something messed up with the permissions of
the "postgres" user; it can't run "initdb" and dies with an "Access
Denied" error. Is there any way to fix this?