Seph, don't feel bad you've not had luck with the levels. I down loaded the image and played with it myself. I had a hard time with it myself. The problem is you have a very ugly color bais going on ( kinda cyan/green thing) your going to have to solve that at the light source. on page 1 I talked about filters. I think you should read it. your going to need a little blue and a little magenta over your lights ( very light shades) The reason it is affecting the the image when you use the levels is, when you set your black point where it should be that evil color jumps out. when you try to fix the color balance. It shift around so much that you end up with more problems. I did have some success but it took alot more than levels.
Make sure all your light are of matching color balance. get a white card to reflect light into the shaddows. And make sure your camera is set on the right color balance for your lights. And try to find a very light magent filter. For over the lights or len. Experiment! you have to find a way to kill that Evil bais.
Good luck, keep me posted
Scott
P.S. you might try a different type of paper, the bais maybe comimg from the surface your shooting on