You either: A) Clicked on a link that is no longer accessable and/or is deleted,
B) The file has been renamed (e.g. something got renamed intentionally), OR
C) Something broke and this page just randomly happened to show up.
Regarding the file, I dunno where it is. I wish I knew, but I don't. It's possible that the file was removed by me for reasons I won't disclaim, or the file just didn't even exist in the first place. Here's what you can do here on this very 404 page:
-Explore this site, or basically all of Neocities if you so choose (come on, it's fun! come out and play with the creative sites people hahave made), or
-Click this back button here or the back button on your browser.