After uploading Max's Pitch Data I get a message saying, "The matching field you chose (Pitch ID) is not mapped and is required for an Update and Insert operation". This is the first error message I have seen from this step.
Sorry you're stuck but there's almost always a pretty easy fix! Do NOT try to start all over again, uninstall Max's Pitch Package, etc. That can make it worse. There's a 95% chance the same snag/fix is listed & answered in the Help FAQ. But if you can't find it there, post your problem here.
Make sure you post in the right category below & be sure to include a screencap showing the issue!