If you get the error below in your event viewer
Console Configuration File Error: XML Exception: Object reference not set to an instance of an objet
and the message Object reference not set to an instance of an object! at the area where you would expect your page editing toolbar then the reason is that the xml files in Editing Menu folder in the Master Page gallery are not in the Published state.
To fix this, just publish all the xml files in the folder Editing Menu and approve them!