I am also having freezing issues on my Macbook Core 2 Duo (generation previous to unibody) with 4 Gig RAM, running Logic Pro 8.0.2, using a FF400 interface updated with latest firmware and FM software. I am running Snow Leopard (10.6.2).
It seems if I turn on the FF400 before I turn on the computer... then I can open up Logic and things will generally work; however, sometimes Logic will still crash seemingly out of the blue and either throw me out or lock up my computer completely (I can't even do a Force Quit or Cmd-Tab to other open applications).
If I have Logic open and then I turn on the FF400 I am definitely getting booted or crashed. And if I have the computer running (but not Logic) and I turn on the FF400 and once it loads, I open Logic, I still get problems. Hope this helps to get this resolved quickly. It is very frustrating.
I also had a problem inside of Logic (and maybe this is a Logic issue but I am mentioning it)... I was in the Environment creating a multi-instrument to my Motif ES8. When I double-click on the Channel numbers (1-16) on the instrument I newly create, I should be able to edit the program and bank... to edit the voices... but Logic opens and immediately closes the window. If I double-click and hold the 2nd click, the window sits there and I can see it is trying to be instantiated... but when I release the mouse button it immediately closes. Doing this a few times, I've had Logic then completely freeze and/or crash on me and boot me out! Maybe this is related!?!?
I am also having some crackling noises from time-to-time. I need to see when this is happening and if its consistent. Two days ago I was typing on the computer and I was hearing the crackling through my headphones. As I was pressing keys randomly on the keyboard, listening to this, I got blasted with a mid range frequency through my headphones. There was somethings triggering it through my mic plugged into channel one. Yet there was no sound in the room to create any sort of feedback loop. After I threw my headphones off, I quickly unplugged the mic from Channel 1. Sound went away. Again, I had NO SOUND coming out of any speakers... nothing playing that would create a feedback loop... and there was no build up anyway... it was just a sudden blast of sound in my years. I was only typing some keys on the keyboard listening to some electrical static I was hearing. I will have to see if I can recreate it today and repost if I do.