You might want to load soundcore first. Or install the modules and do a depmod -a and then modprobe instead of insmod. I had the same problem. Sadly, up until 2.6.15 loading up soundcore hangs my imac so I haven't been able to go past that ...Its snd-powermac that hangs your imac, not soundcore I think
You're right! Thanks to your comment I was able to test the new snd-aoa drivers.