AppletIntegration Addon

General
1

Well, I am using the vaadin AppletIntegration Addon to integrate my sound recorder applet with my vaadin project.
Here is the code :

              AppletIntegration applet = new AppletIntegration() {

            private static final long serialVersionUID = 1L;

            @Override
            public void attach() {
            	System.out.println("In attach functions");
        		
					setAppletArchives(Arrays.asList(new String[] { "SoundRecordingJar.jar" }));
					setCodebase(path);
					setAppletClass("AudioApplet.class");
					
                setWidth("800px");
                setHeight("500px");
            }
        };
        mainWindow.addComponent(applet);

When I run it in browser :
It gives me the following error :
java.lang.ClassFormatError: Incompatible magic value 1008813135 in class file AudioApplet

If I run the same applet with html file, it works fine with no exception. The applet is signed also.

So,
What does this error mean and how to solve it.