Hi btmspox, and welcome to the VMware Communities!
Sorry for the hassle you've run into there. We've identified a glitch in the Fitbit gizmo which causes the Fusion Tech Preview crash you've encountered. We have implemented a workaround for the issue which is now in our internal builds of Fusion and will be in future releases of Fusion.
Thanks for your participation in the VMware Fusion Tech Preview 2013 and for your concise and wonderfully detailed report!
Cheers,
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Darius