Key light out of memory?!

[txdp]

I'm getting an error "key light out of memory" in after effects cs5.5 2010 iMac w 8gigs ram. I'm keying a 5k movie made from a still image sequence. Any ideas on what to do? I've searched google but found nothing helpful. Anyon seen this?

[Ewan L]

By the sounds of it, your computer doesn't have enough RAM to do this.. I thought 8GB would enough. Try closing background processes.