iMapBuilder for Windows has limited support of HTML in the text boxes. If you want to place an applet or other media plugin into the information box, we would recommend using our Google Map Builder from iMapBuilder Online. You may sign up a demo account here:http://www.imapbuilder.net/login
and choose "Custom Google Map" from the start screen.
We suggest testing of the code in a plain HTML page to ensure that the applet or plugin works, and make sure that the HTML code is well formed for proper function of your applet and the map.