Problem with Guitar Rig/ electro acoustic...
I'm presuming your setup is guitar into Presonus then into an audio interface before going into Guitar Rig (or Amplitube etc) . Decent leads also seem to be hard to find in 1\4" jack mono to RCA; the ones I'm using are admittedly pretty poor, but I'm restricted by the available inputson the Audiophile.
MacBook 2Ghz, 2Gig RAM, Auidiophile FW, softsynths and audio