Originally posted by spiral light:
I had this happen before, it's your soundcard. You need something more heftier than SB Live if you want to record audio (I use a midiman delta44 and have had good luck with it). The other option is to go in via USB 2 or Firewire (both faster than standard usb), this opens the door to mixer/input hybrids from tascam (eg). SB Live is ok for playing back, just not recording.
Good luck!