Leigh,
Did you know you can download a working Oracle 10g VM from VMWare?
http://www.vmware.com/vmtn/vm/oracle.html
And you can run it with the free VMWare Player.
http://www.vmware.com/download/player/
I bet it will take you < 30 minutes, and leave your host system in much better shape.
Only problem is I'm not sure OpenACS will install it's data model on 10g ...
John