If those are your live API credentials you need to edit your post and mask those out right away. You never want to share those values with anybody.
If the SetExpressCheckout request is failing then you would have no token. This seems to be reflected in the DoExpressCheckoutPayment request you've posted here, as there is no token included in it, which is why you're getting the invalid token error.
That said, when the SetExpressCheckout call fails you should be seeing an error right then and there. Are you actually getting redirected to PayPal and back? That would be very odd of SEC failed. There must be something else going on here.
I'd have to get a more direct look at your setup to figure this out. Please contact me directly so we can work on this together.