Where can i find a 5.1ch Cable?

I was given a 5.1ch Curtis DVD 5041 Home Theater system, and i'm missing the cable that goes from the DVD player to the Subwoofer, it is labeled as a 5.1ch cable, it's a 9 pin DIN style cable. It almost looks like an S-Video input type of cable, except it has 9 pins . . . Where can i find this cable? i have been to best buy and radioshack and other electronic stores. thank you in advance.