Several things were tried but still have the same problem. Below, I listed the things I tried but didn't work.

The HTML markup of the applet was changed which partly worked. When viewing the applet in an offline page, it showed the new version.

<param name="cache_option" value="No" />

That didn't work in the version on my website, though.

Firefox temperary internet files were deleted but it the old version of the applet is still shown.

I went into the AppData\LocalLow\Sun\Java\Deployment\Cache folder that the JVM seems to use to cache its jar data and deleted most of the numbered folders there.

A similar question was asked here but the solutions given to that don't work for me.

The web page containing the applet is here. The old version starts with a semetric view with the stop light and stop sign in dead centre. The new version looks off to the side by 30 ot 40 degrees. If I'm right, you should see the new version and things off to the side.