Be my guest.

Ok let’s start with the native SU before we get onto the VRay.

Couple of things:

You need to pay attention to the front and back faces. (front – white , back – blue).
VRay materials should only go on the front faces. The front faces are for external surfaces so with a brick wall for example, the outside (the bit you see) should be white and the internal (the bit you don’t) should be blue. http://support.google.com/sketchup/bin/answer.py?hl=en&answer=115427
Your model needs to be all white inside the church. The attached file (stage feb 24 edit Monochrome.jpg) shows what faces need to be changed.
stage feb 24 edit Monochrome.jpg

You need to keep up with purging the unused materials, components and styles. I ran a purge and the attached file (Purge.jpg) shows how much unused stuff was in it. The files is greatly affected, the file you sent was 20mb and the purged file is 4mb.
Purge.jpg

On to the projectors screens:

The reason they weren’t working is because they had been applied to ‘back faces’. I have attached some file that should help explain it.

This image show that on is not working but the other is. (Screen 1.jpg), the corresponding SU export shows the one not working is applied to a blue face. (Monochrome 1.jpg)
Screen 1.jpg
monochrome 1.jpg

As you can see in (screens.jpg) they are both working and the SU export shows that they are both front faces (monochrome 2.jpg)
Screens.jpg
monochrome 2.jpg

I have attached the reduced file as well as the packed material.

Hope that helps.

TRJ - stage feb 24 edit.zip

TRJ - TV screen.zip