My "SweetHome3DApplet.html" has an entry:

var jars = "lib/SweetHome3DApplet.jar,lib/Loader3DS1_2u.jar,lib/batik-svgpathparser-1.7.jar,lib/jnlp.jar"

But the directory does not contain SweetHome3DApplet.jar
In the folder there SweetHome3D.jar, all right?