Have you lost your original Creative CD?
if so try downloading from here - assuming XP. If you want to get onto Vista, you need to find a friendly XP owner and get the music onto XP first, then upgrade the firmware to "plays for sure" from the creative web site.
Here's the XP download site - includes the "plays for sure firmware"
dealing with Vista is here:
click here(16737),Kb=ww_english_add,VARSET=ws:click here
I repeat: before you upgrade your firmware, you MUST back up your music!