It looks as if you've found the door to nowhere.
We're sorry that we didn't lock it, put up no entry signs, a liability disclaimer and a large, scary dog. Clearly, someone among our web development team needs to be punished, and we can assure you that justice will be swift. We've logged the error and will investigate thoroughly. Don't feel at all to blame, it's not you, it's us, and by us I mean you, Nigel.
If your name's Nigel, then we'd like also to reassure you that we mean our Nigel, not you.
I think we may have over-thought this error page.