Digital Clicks, Crackling, Snating with AU version

[electropiano]

Whenever the GUI is engaged we get clicks, break-up, snating, etc.
When we use the AU without the GUI (in Live either in Snow Leopard or Leopard) the break-up stops.
We would really like to use to GUI to see what we are doing when we have our 5 loops working.

Is this a known problem? Is there any remedy?
Is this a coding issue?
It forces us to work in the dark, guessing at what is engaged.
(it's troubling because the pedals don't always engage)

[jesse]

What is your hardware? What audio interface do you use? How much other stuff is going on?

I haven't really heard of audio breakups on OSX due to GUI usage before...