[Takara]

Just a note, in the instructions it says

In the .htaccess file, locate any lines beginning with "ErrorDocument". Erase those and replace with the following code. If you do not have any lines like that, just add this at the end of the file.

ErrorDocument 400 http://www.yourdomain.com/forums/error.php?error=400
ErrorDocument 401 http://www.yourdomain.com/forums/error.php?error=401
ErrorDocument 403 http://www.yourdomain.com/forums/error.php?error=403
ErrorDocument 404 http://www.yourdomain.com/forums/error.php?error=404
ErrorDocument 405 http://www.yourdomain.com/forums/error.php?error=405
ErrorDocument 406 http://www.yourdomain.com/forums/error.php?error=406
ErrorDocument 407 http://www.yourdomain.com/forums/error.php?error=407

If you just add the path, and leave out your domain the error document will take the place of the URL.. soo.. by going to dasdsa.php it leaves the url as dasdsa.php and gives the error reason. Otherwise it redirects you to the error.php ^^