Your soundcard outputs either a digital optical or analogue.
The easiest connection type from a SB Live 5.1 sound card to AV receiver will be an optical 3.5mm jack to Toslink cable (the type of lead used to connect a portable minidisk player etc to an AV system)
The analogue connections required would be 3 stereo 3.5mm jack to 2 phono leads
Just had a look on the Soundblaster web site, and it seems that the card has a digital co-ax output. Assuming that this information is correct, you will need a cable such as QED's P-75. Other cables to consider are Ecosse's Producer.
You need to be careful with sound cards, they all have different connections, I have seen sound cards that use 3 pole 3.5mm jacks, stereo 3.5mm jacks and mono 3.5mm jacks for digital out, in addition to the TOSLink and minijack optical.
Do you have the manual to hand, it should tell you.
i dont have the manual sorry, i have the bare card and looking at the card i cant tell whats what on it, i had a feeling the biggest one was a Co-ax though, will pick up a co ax cable as soon as i can.