Floor is Darker than Background?

I haven't seen any problems with this anywhere else so I don't know what's up.
Basically, I have added a PNG sequence and animated it onto both the Background Layer and the Floor. The background is as it should be, however the floor is darker when I render it out. I don't think it's a matter of lighting since I've done this sort of thing many times without lighting and it's worked just fine.

Also, when my friend creates the same thing with a floor and a background and I load it on my computer it works just fine, making me think it's not something wrong with the installation and whatnot.

Here's an image to show you what I mean:
http://gyazo.com/dc0846ac637b731ac840013a7cca28e3
The darker part of this render is the floor.

Thanks.

Add a compositing tag to your floor by right clicking your floor layer > cinema 4d tags > compositing and enable "compositing background". U have to render to see the effect.

Grtz Ruud