I don't want to give you false hope, LDD, but I would think that's a good sign.

If they thought your application was borderline or inclusive enough to warrant an exam by their doc, I would think they would need to have documention from him finding no disability to cover their butts before denying you. I would think canceling your appointment meant they found something more conclusive in your records or received more records on you that swayed them in the "right" direction.

Of course, this is the government, so logic might not apply

I hope that you get word on a decision soon. I know how frustrating the waiting can be.