The most irritating message when you try to run any applet you get. Sometimes even if you installed the below mentioned J2SE plugin, it still does not work.
I got the same issue and I uninstalled all of my Java versions first and then I installed the below mentioned Java plugin and then it started working fine.
In order to access this application, you must install the J2SE Plugin version 1.6.0_07. To install this plugin, click here to download the oaj2se.exe executable. Once the download is complete, double-click the oaj2se.exe file to install the plugin. You will be prompted to restart your browser when the installation is complete.