Is anyone experiencing conversions with no SubID's?
My prosper is tracking a few conversions from the post back URL, but it's not recording all the revenue from what I see in the GT dashboard.
I've had this problem too and its a real pain. It's caused by users who don't have cookies/ javascript enabled and therefore the subid doesn't sent to GT. Sadly there isn't much you can do.
Thanks for the input. It does suck indeed, nearly 60% of my daily GT revenue doesn't have a SubID. 
Did you check your code thoroughly?
I just send the subids to gt and export them.