How to use Effect_Screen_Start?

[WALP]

I'm trying to use Effect_Screen_Start to fade an image on the screen, but I have only been able to produce a pure black screen, or a solid color if I add an illumination image to the material. this is the code I am using for my test:

Effect_Screen_Start("wholeroom1.png",cVector2f(0.5,0.5),cVector2f(1920,1080),1.0,1.0,1.5,1.0);

and attached is the .mat file.


I have tried changing the resolution, adding alpha channel, changing the vector position, changing the image type(tried .dds,.png, .jpg.), with mip maps and without, using FG images, so I really just don't know what it is I need to do to get this working.

EDIT: and before someone asks, I did try both with and without the ".png" after the name
EDIT: forgot to include the image file in the zip, now fixed so it includes both the .mat and the .zip