The file has either been moved or deleted, or you entered the wrong URL or document name. Look at the URL. If a word looks misspelled, then correct it and try it again. If that doesn't work backtrack by deleting information between each backslash, until you come to a page on that site that isn't a 404. From there you may be able to find the page you're looking for.
You may also to visit to visit the home page at: http://coogan.net