Chances are if you're seeing this error it's either because you pressed the 'GO' button in very quick succession (you have quick fingers), in which case - apologies - just refresh the page after a couple of seconds and everything will be fine. However, it's far more likely that you are a nasty web-scraper who is just trying to suck content from this site, in which case - bog off!
If this error persists, please contact your mate who does a few web-sites, or that bloke from down the road that works in I.T., or try switching your computer off and on again, or prodding the screen with your finger, or a blunt stick.