When I do a search on this site, I get a page of links as per normal. I click on a link, then use the back button, via mouse button and / or browser menu bar, and instead of returning to the list of links I get an error message showing the folllowing:

Click image to enlarge

It does that to me as well but if you hit 'refresh' (F5 I think) the PC will do the search again for you and you should get your results back.