---- dataentry configoptions ----
type             : constant
name             : ERROR404PAGE
purpose          : Allow a custom file-not-found page
allowed          : filename in webroot
default          : 
status_s         : 
category         : system
----

Set this to a file that can be found in the webroot of the site that phpList runs on. If this file exists, it will be used instead of the default File-Not-Found to display when a link is used that is incorrect.