Quicktime is not installed correctly.
It appears that the version of QuickTime that you have currently installed is out of date. Upgrading to the current version is free, and will allow you to view the presentations on this web site.
You will be automatically redirected to the QuickTime download site in a few seconds to install or reinstall Quicktime, which takes only a few minutes, and solves this problem (follow the directions to download and install the "Free Player"). Click here if you are not redirected promptly.