Here is a copy of the test files I got from fedex.
Extract that to your site so you can test.
From what I gather you should just have to enter the correct credentials on the fedex-common.php page and it should work. (lines 73,74)
However I get an authentication error with the information you have provided. If you can work with fedex support to get the correct credentials to get this sample working I can help you integrate it into your site.