Vil ikke indlæse fil med filtypen .php

Jeg har lavet en lille viderestillingsfil, som jeg kalder

dinside.php (filen skal have typen .php)

med følgende kode:

<%
    Response.Redirect "http://Glrejser.dk/book/dinside.php?" & Request.QueryString
%>

Men jeg får denne fejl, når jeg kalder php-filen:

This error occurs when the file extension of the requested URL is for a MIME type that is not configured on the server. You can add a MIME type for the file extension for files that are not dynamic scripting pages, database, or configuration files. Process those file types using a handler. You should not allows direct downloads of dynamic scripting pages, database or configuration files.