Magic Bullet now strobes/fields are off

I upgraded to the new 2 x 3 GHz Dual-Core Intel based Mac Pro. Now after rendering Magic Bullet (LS Diffusion effects), the video strobes on movement when played back. It almost seems like the fields are off. I can't figure out what's causing it. I've upgraded to the latest Magic Bullet Suite. I've also got a new Black Magic Extreme HD card (my old card wouldn't fit in the new PCI-extreme slots!). I'm using the DV50 codac.

Thanks for your help -
Scott