Here is the solution for those people having problems tethering their Sprint Blackberry 8830 to their Mac (or PC). If you are using the WWAN Support script (this is the correct one by the way) for the Mac (using bluetooth) and you are connecting and then disconnecting with the log saying that the script failed, it's a provisioning problem. If you are attempting to hard tether your 8830 to your PC and getting a #678 error, it's a provisioning problem.
Call Sprint and tell them to push your provisioning again. After almost 2 weeks of horrible tech support, I finally found a guy that was OUTSTANDING! He covered every angle and got it re-provisioned and it worked perfectly. He also fixed my text messaging on my account. I can't tell you how different this call was from all the others. I'm writing his supervisor (and cc'ing him) about the excellent job he did. That phone call was going to be my last ditch effort with Sprint before chucking them, he saved their continued business with me.