Custom Error Documents
.htaccess
ErrorDocument 401 /error/status401.html
ErrorDocument 403 /error/status403.html
ErrorDocument 404 /error/status404.html
ErrorDocument 500 /error/status500.html
Another fine way to approach this would be for each of the different error status codes (401, 404, 404, 500) all point to a single error.html document.
ErrorDocument 401 /error.html
ErrorDocument 403 /error.html
ErrorDocument 404 /error.html
ErrorDocument 500 /error.html