Trouble adding word press

I am hosting through namecheap and have followed this video tutorial
http://namecheap.simplekb.com/kb.show?show=article&articleid=752&categoryid=81

I am at the end of the process where I got to
http://www.nameofmysite.com/wp-admin/install.php

I get the page not found error and see that some of the files had trouble being being transferred and failed to be transferred. Can someone tell me whats wrong and how I can fix it. All help appreciated. Thanks!