A comment from Milos Kleint: "You need to make sure the project is using 3.0 nbm-plugin (as done above), the setup with 3.1 plugin is broken currently. 3.1 is using netbeans 6.7 ant tasks. Someone put some classes in the com.sun.javahelp package there in the ant tasks jar. Which seems to work with the nb.org javahelp jar, but fails with the javahelp jar in the maven repository. The maven repo jar is signed unfortunately and the few additional classes in the same package, but different jar messes up the classloading permissions and the signing fails. which is a pity as 3.1 didn't need the plugin dependency addition, so was simpler to configure.. a workaround I found was to un-sign the javahelp jar in the local maven repo, but that's nasty."
<file name="module1-helpset.xml" url="module1-helpset.xml">
<attr name="position" intvalue="3818"/>
I needed to remove the "search" tags in the "-hs" file, otherwise a "search is invalid" error was thrown when the Help menu item was selected. That should result in other problems but at least the help content is shown and you can search it anyway.