AE CS3 Lights burned out?

I imported a project I was building in AE6.5 into my shiny new copy of CS3 and now the lights don't work. The light was fine in AE 6.5 and casts the correct shadow, but the same exact comp in CS3 doesn't display at all.
Settings are the same, the light is active, the layers that cast the shadow and the layer that receives it are all checked correctly, so any idea what I could be missing here?

I'm not an AE rockstar, but I know my way around well enough to get some pretty decent stuff done. This has me stumped.

Thanks in advance for any suggestions or solutions,
-Andy