IDK if you got this fixed, but i can assure you the 8.1 developer preview didn't break the access point settings (running the latest version). However, access point relies on extras+info, which in turn relies on the OS version, so if the access point options are not operational then you likely haven't updated extras+info and access point. Go into the store settings and check for updates. After a few minutes any app updates (including OEM system apps such as those aforementioned) will begin downloading and installing. Once all system apps are up to date it should work,