Hi furiousmonkey, and welcome to the VMware Communities!
I've been investigating this, and don't have any wonderful or truly helpful news to share as of now. I will mention, however, that if you boot a physical Mac (host) into Safe Mode (hold the Shift key before the Apple logo first appears on screen), you will find that the Java 7 Control Panel crashes in exactly the same way on that host, even when Fusion is not present at all. Hmmmm...
Cheers,
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Darius