I am sorry, please do not get me wrong, I copy-pasted my last post from a different topic, so ignore the "as suggested everywhere". You have to chmod to 777 for the Apache user for the cache, tmp, config and upload folders in order to have the right permissions to run the application
Regarding the upgrade, it does take several minutes to do it.. you will see the screen changing once the upgrade has been done successfully, but you have to be a bit patient.
Best regards,
Francisco