[imp] Login: mailbox downloads

[Robert Oliver]

Having a problem I've seen others post, but have not seen a resolution 
posted.

When I attempt to log in from the URL 
http://mywebsite.com:/horde/imp/index.php instead of logging in, I 
receive a pop-up dialog from the browser telling me that file "mailbox" 
is being downloaded, and asking if I want to open/save/cancel etc.

At one point, before modifying configurations, I was actually able to 
log in, but could not see any messages in my mailbox. Clicking on the 
mailbox would then give a file download. Wish I could figure out what 
changed there; might be a clue.

New Horde/IMP installation with Horde 2.1, IMP 3.1, Apache 1.3.6, PHP 
4.2.3 on Win2K. I'm completely new to Horde and IMP, and pretty much a 
novice at Apache and PHP as well.

In http.conf I added

DirectoryIndex index.php
AddType application/x-httpd-php .php

This must be something obvious to those who know the architecture. Any 
and all help greatly appreciated! I'd love to see what IMP is like!

Robert Oliver