.htaccess for custom error codes

[son]

Have the following in .htaccess

ErrorDocument 401 /401.phpErrorDocument 403 /401.phpErrorDocument 404 /404.phpErrorDocument 500 /500.php

and works fine for web root requests. However, does not work if wrong file accessed within a directory. Have tried to have full system paths and is the same situation. Do I need to have .htaccess for each folder then? Or how can I improve this? Thanks,Son