Unfortunately, even when following Apple’s instructions for getting push notifications going, I ran into this error:
Error in registration. Error: Error Domain=NSCocoaErrorDomain Code=3000 UserInfo=0x1402f0 "no valid 'aps-environment' entitlement string found for application

As it turns out, I needed to give myself an entitlement called ‘aps-environment’, whereas I’d assumed (and I’d found nothing on the internet to contradict it) that this was an internal part of the provisioning profile, since Apple recommended I created a new provisioning profile once I’d activated APN on my application in the development portal.

This document from Apple explains how to do this.

I’m sort of hoping this helps somebody in the same flummoxed position as I