There are three error messages already configured, 404 (not found), 500 (internal server error) and 403 (forbidden). You can easily add, edit or remove the error types as needed.

The main error that this module will deal with is the "404 file not found" message - this one also has a handy search box, which should help keep misdirected visitors on your site.

Error messages can be logged to help you track them, which is handy if you find another site is still linking to a file no that longer exists, or a page/script keeps failing.

This module is written with Apache in mind, so also needs the .htaccess file in the site's root folder (it should also work in other servers where you can add custom error messages) - AM HTError can not write to this file itself as this would be a security issue, so you will have to manually edit this upon first installing the module, and every time an error type is added or removed. The text for this is generated automatically in the module's admin index, and only needs to be copy & pasted.

Version 0.05 (beta) can be downloaded from here.
An example of a 404 error message can be seen here.