Installation problems like this are hard to diagnose from a distance, but I can give you some advice about what I do when I run into such a problem:
Before you do anything else, make sure that the version of the application you want to install is supported on the version of operating system you are running.
The first thing I do is to reboot the computer and then attempt the installation again before running any other applications. If that does not work, I disable my virus scanner. If that still does not work, I try to install as a different user on the same computer. If that works, and you can install the application for all users on that computer, you should be all set. If it still does not work, then it's time to get in touch with Adobe's customer support.