[Bug?] Imod 141 Asking me to download php file

I have a very annoying problem.
Every time I click on the profile link, or private messages link, index link, portal link etc, a box pops up asking me to download whatever file belongs to the link I click.
Example, I click "Portal" and the box asks if I want to download portal.php
This used to happen to me all the time on this site but now it's happening to mine.
The weird thing is, it happens to All of my sites. I have several sub-domains made for different things
Main site
-Main Forum Design site - http://www.black-fusion.com/forum
-IntegraMOD 140 Test/Theme site - http://www.black-fusion.com/imod140
-IntegraMOD 141 Theme Porting Site - http://www.black-fusion.com/imod141
etc...
Every one of the sites do this now..
Anyone have any idea as to why?
Every time I click on the profile link, or private messages link, index link, portal link etc, a box pops up asking me to download whatever file belongs to the link I click.
Example, I click "Portal" and the box asks if I want to download portal.php
This used to happen to me all the time on this site but now it's happening to mine.
The weird thing is, it happens to All of my sites. I have several sub-domains made for different things
Main site
-Main Forum Design site - http://www.black-fusion.com/forum
-IntegraMOD 140 Test/Theme site - http://www.black-fusion.com/imod140
-IntegraMOD 141 Theme Porting Site - http://www.black-fusion.com/imod141
etc...
Every one of the sites do this now..
Anyone have any idea as to why?