Actually, the changes you made on the value of the jars variable and codebase attribute have an effect only with Java 6. Under Java 7 and further, I think that the JRE always uses the jnlp_embedded parameter after decoding it from Base 64.
As the jnlp_embedded parameter proposed in the default configuration tries to download jar files from lib subfolder, that would explain the error you reported. To fix it, you should download the SweetHome3DViewer.jnlp file that was used to generate the current value of the jnlp_embedded parameter, update the href attribute of its <jar> elements with a text editor and save it. Then, convert the modified file to Base 64 and copy the encoded string in jnlp_embedded parameter.

By the way, there must be a typo in your homeURL parameter where a colon is missing after http.