If you're trying to use an application that was released a very long time ago on a newer operating system, then you can expect errors. Otherwise, reinstall the software and this time make sure to run it as Administrator. As far as I know, Adobe After Effects doesn't have many issues when it comes to loading the main program. However, terminate all the background processes as well and then launch the software again.
Also, download a new installer through the official website: http://www.adobe.com/products/aftereffects.html
