Just to complete the correct answer: You will need the media package to get the "flash" class installed. The flash class and its embed templates will create the HTML, which you will need to display the flash files in your HTML page.
All of the optional packages that are provided by eZ systems can be found here: http://packages.ez.no/ezpublish/3.8/
Including the media package, which contains classes and templates for quicktime, flash, windows media, and real player.
To load the package, download it then use the Setup/Packages area of the admin to install it. There is an installation wizard that will take you step by step through the installation.