Back button dont work in web browser and plugins dont load in posts…

I have a really weird and annoying problem on my homepage.

When navigating through my site, the back button (history button) work as it should. But as soon as I have clicked an image, the back button don’t go back… But if I click back once, and then refresh once it will reload as it actually has gone back one step but not reloaded the page???

The same problem is with my facebook plugin and fancybox plugin.
They don’t load into my posts, but as soon as I reload the page once, the facebook’s comments and like button appears as it should. And also the fancybox works….

I have tried to disable ALL plugins, but the problem still persists…

Any idea on what to do??