On your way in you may have missed that we have a policy on screen names here at JavaRanch. Basically, it must consist of a first name, a space, and a last name. Since yours does not conform with it, please take a moment to change it, which you can do right here.
As to your question, that error often happens if a class that's needed by the applet can't be found, or if there's an error during initialization. Check the Java Console for error messages; there should be something in it. Also make sure that all classes and jar files used by the applet are publicly accessible, and that all jar files are listed in the applet tag.