Oh, it will use it's own web server by default: Webbrick, listening on port 3000 on a standard install. You maybe already know this and have it working with apache2.
I'm happy to help if you have setup problems, if only to spare someone else going through what I went through. My server is running nginx and postgres from compiles and I am currently writing a script from my bash history, which I will put on github when I feel it won't create any embarrassment for me
EDIT: I should have read properly, you are using passenger. I gave up on passenger eventually, opting to go manual. Not sure how good it is with Apache though.
Your file not found implies a passenger problem. Are you pre-release? If you are then you might want to consider just getting R&R installed via RVM and Gems first, then getting passenger working later.
There should be a database.yml in the config folder of your project by the way.