I need help

I am new to wordpress on my server. I have used it on my schools server, but I want to move onto my own.

The links for my problem is

http://theteam.ath.cx/wordpress/

Well that part works, but when i go into the

http://theteam.ath.cx/wordpress/wp-admin/install.php

it just shows the code, I think it has something to do with the permissions not set right so people can execute the php file. But on the other hand. The index page is in php (first link on top) and that can be read easily, so i don’t know, help anyone?