Sound Blastter Audigy with a 5.1 external receiver

I have an intalled woprking soundbalster audigy platinum with the live drive in my computer i got tired of my comptuer speakers and my klipsch 5.1's broke so i threw a home theater 5.1 decoder on here and some jbl speakers w/ a sub and connected the receiver to the comptuer via the optical port on the front of the computer. but i donlt get left and right sound. no rear no center and no subwoofer durring games or windows does anyone know why? do i need to use a different connection to hook it up?
thanks alot
-Visual

i know... tahts the problem am having what cales and what connetions should i use to make it work is really my question any help would be greatly appreciated

build it and it shall play

if thats your problem then didnt my message just explain to you on what cables you need and from what to where?? O_o

---
...and with every tear a dream.