Java Programming

As part of a project I'm currently working on, I've implemented a series of Help pages in HTML, which are accessible when clicking a JButton inside the system. I've made use of the previously created [BareBonesBrowserLaunch.java|http://www.centerkey.com/java/browser/myapp/BareBonesBrowserLaunch.java], and when running the project through Eclipse it worked fine, loading up the native browser (Firefox in this case, when using Windows XP) with the specified URL.

But when packaging the project up as a runnable JAR archive, and then running the system through that, the buttons stop working, without throwing up any errors at the console. The problem line seems to be

Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler " + url);

as any print statements before and after come out fine, with no exceptions being thrown on the line itself. I tried replacing that argument with a simple "mspaint", and that worked fine within the JAR.

Any ideas why it's not working? I thought maybe it was something to do with not being able to access the registry on the computer I was working on (University computer) but it's the same problem on mine and a colleagues laptops.

Any help would be much appreciated, this help system is pretty crucial to the system as a whole.