Optical Digital Audio MacBook

I just purchased the mini toslink optical audio cord so I can connect my MacBook up to my digital receiver to play music through. I have connected it but now I cannot get any sound to come through. I have played through tons of settings but cannot figure out what the problem is. The best I have been able to get, out of luck, was sound out of the center speaker but now I cannot even get that to come through. I was wondering if anyone could help me get this thing set up. I have a Bose sound system hooked up to the receiver if that matters at all. The sub is also not working. Please help! Thanks