adding PDFs

I found the file that needs to be changed in the new version of Power CMS. It is the config.php file located here -
HTMLEditor/editor/filemanager/connectors/php/config.php

Go to approx. line 142 and add , 'pdf' (don't forget to separate with a comma).
$Config['AllowedExtensions']['Image'] = array('bmp','gif','jpeg','jpg','png', 'pdf') ;

Then you can use the Insert/Edit Link icon to upload the PDF. I like to always set Target=Blank and leave the protocol as other. It works absolutely fantastically!

I decided to then try Word, Excel, and Powerpoint. They all work except I can't get the PPT show file to work (ppst). But that's ok. I'm happy with everything else.

What I don't understand is why these files don't upload w/o this fix to the config file. The file extensions are already listed in other lines of code. Could someone please explain that to me? Just curious.

Again - you can check out my testing page.
index.php

thank you,
Laura