No Sound through Digital/Optical Out

[diesel00]

I have connected my Macbook to my AV receiver/amp via a mini Toslink to standar Toslink cable. The Mac recognizes that it is attached to a digital output under the DVD Preferences but there is no sound through my receiver. My amp is set to receive the Optical signal and my DVD player works fine through the same input, so I know the amp connection works.

I have connected the Macbook to my 1080i TV and wanted to watch movies with digital sound.

I have done multiple searches on this website as well as searched using Google, with no fix.
I have already ensured the settings in the DVD Player are set to send the Digital signal, I have re-started the computer and still nothing.

Please Help.

Macbook 13" 2.4GHz Mac OS X (10.5.4) 2GB Memory, 160GB HD, Double Layer Super Drive

 

[KoolStar]

Check the sound preferences that the audio out is actually selected as digital, not the dvd settings.

 

[diesel00]

I have attached a screenshot of the Sound preferences from the System Preferences and the DVD Preferences. Can you tell me if this is what it should look like?
I wasn't given an option to change the Sound Preferences. Once I plugged in the Toslink cable it auto changed to this.