I just noticed you are trying to access the page through mysite.com and the admin pages through mysite.com/admin. You installed your Powerstore in a sub-directory, not in the root of your site. You will have to access the PowerStore from mysite.com/PowerStore300/ and mysite.com/PowerStore300/Admin/
If you want the PowerStore to be accessed from mysite.com and mysite.com/Admin, you will have to re-install the files at the root of your server.