Are you using a supported browser? The email2 web client interface currently runs best on Internet Explorer 6.x and Internet Explorer 7.x. Due to the interactivity of the page, you must have Javascript enabled.
Since the email2 Web Client Interface is such a rich environment, you must have a screen resolution of at least 1024x768.
Some aspects of the web client interface (for example, the voice and video player) require Adobe Flash Player 8.