Comment 21 for bug 84501

The problem is that the sun-java6-javaws.desktop is incorrect. It currently runs the viewer:
Exec=/usr/lib/jvm/java-6-sun-1.6.0.05/bin/javaws -viewer

It should just be javaws when you want to send it a java webstart app so it should be this:
Exec=/usr/lib/jvm/java-6-sun-1.6.0.05/bin/javaws

You can test this by launching a webstart app from the command line and you will see that with -viewer it doesn't work.

There really is no need to launch the cache viewer this way, it can be found by running the control panel, and clicking view under Temporary Internet Files.

Thanks!