The problem is most likely your choice of browser. Netscape generally has
good, current support for Java. Unfortunately, Internet Exploder does not
have full support for Java 2, even though it is over 2 years old. Even
basic functions like Double.parseDouble() are not supported.
If you have the misfortune to be using IE, you can use its menu to enable
a Java console window. You can then restart the browser and run your
applet. The Java console window will tell exactly which feature you are
trying to use that MS has refused to support.