Hi Xgipper, ditto for me too. Almost identical problem except my Macbook Air is OS X 10.7.5 64-bit. Everything else you describe is absolutely identical even down to the fixes above not solving the problem.
As an aside Opera is working fine on my Windows Desktop PC (on which I'm submitting this post)

xgipper are you able to sign in to your Opera account? I'm unable to since this problem has started.
Also, several site are okay: Google Maps, Calendar, Trip Advisor, Google News, Gmail...