Is it on Unix? I think on most unixes, mozilla is a script that at the end runs mozilla-bin (or generally does something). So when you try to destroy the process, it actually doesn't run anymore anyway.
You might try running directly mozilla-bin, which I don't recommend. I know that this isn't going to be very helpful, but can't you just let it run and leave it to the user?
Get a better web browser:<br /><a href="http://www.mozilla.org/products/firefox/switch.html" target="_blank" rel="nofollow">http://www.mozilla.org/products/firefox/switch.html</a>
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com