I see those buttons in Facebook. When the social buttons are missing in a browser, it almost always is caused by an add-on/extension in the browser that is blocking them. Things like Ghostery, some anti-virus and other 'privacy' extensions that are meant to stop websites from tracking or analyzing you will prevent some social features from working.
I'd recommend checking your add-ons to see if that helps fix things. If not, try from a completely different computer.
Thanks,
Alex