After completing Lab 1b I went through the grading process and it showed I had to errors. I went back and corrected the errors using the steps provided. I went back to re-grade my work. Going through the process, it listed a grading error. I retried re-grading the work, and even redid all the corrections, but the same message appeared.
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!