Help with Clean White Continous Background

I'm trying to get my background clean and white without having to do a lot of PP work on it. What am I doing wrong?

I'm using a paper roll of Super White and two full spectrum 55 W CFL Daylight 5000k in hood on stand.

I'm then using SB900 in a softbox as the key light. I sometimes use an additional SB600 aimed at the paper but that doesn't really seem to help.

Do I need more lights?

Thanks,

Brian