Upgrading from 50/34 to 50/39 with Shimano Sora?
Take a look here http://www.vueltausa.com/components/chainrings.html
It looks like the flat series is for single speed or old style 5 or 6 speed non indexed shifting bikes.

Suggest you need the SE Plus range http://www.vueltausa.com/components/chainrings/se-plus-chainrings.html which is designed for 7 to 9 speed. It should be narrower than what you have, which may be why the chain is fouling.