SBS 560 5.1 system problem

I have an Audigy and a SBS 560 5.1 surround system. In 5.1 mode, the center speaker will test to work (using the diagnostic test, the lady speaks through the speakers)... but nothing else will come out of it! So I have it in 4.1 mode right now... but I want my center speaker to work like it should! I have reinstalled the software/drivers, and even swapped out the Audigy card with a new one. IT STILL WON'T WORK! Only 4.1 What is the problem?

SO NO ONE HAS ANY IDEA???