Just gonna throw my 2 cents in here (Apple Certified Technician & Technical Co-Ordinator. System, Network and Infrastructure Engineer) as i know a few things about computer troubleshooting…

Is the issue persistent after performing a Restart, SMC or PRAM reset of your mac, how about if you boot to the recovery partition or know good OS then open Disk Utility with the card and/or octatrack connected?
What happens you if you connect a different card to your mac or your card to a different computer, does it show up? This list could go on…

I know that troubleshooting an issue is a frustrating thing to do and that it’s easy to get pissed off and loose your cool…Try taking a step back, approach the problem in a methodical & logical manner.
Use the split half search method (google it…), making note of what action you performed and it’s outcome. Don’t just point a finger at something you think it could be when you haven’t taken the correct steps to isolate it…

If you are still convinced that it is the computer then take it to an Apple Store and yell at the poor muthafuckers behind the Genius Bar, they get paid to deal with dickheads…