Reason 2.0 digital noise problem help???

[Bithmaestro]

I would appreciate if any could help with this problem......
I'm running Reason 2.0 w/ Fatar Studio 90 controller. There is an unusual digital noise when I play the controller. I'm connected through an Alesis QSR sound module that uses an optical cable that connects to my Mac G4 867mHz. I also have Pro Tools LE 001 connected to the Mac with the normal pinned cable. All of these devices are connected to a small mackie mixer. When I use every one of these devices no digital noise at all, but when I launch Reason and have the midi talking to the 001 in Reason it happens. If I setup the prefrences in Reason to built-in instead of 001 then it stops, but then no sound from keyboard. Is there a way to fix this??? Anyone had this problem or a similar digital noise?? Please help!!!!!!!!!!!!!

[jake-owa]

What does it sound like?

[Bithmaestro]

It is a pop, crackle kind of sound when playback occurs