Yes...I had the same problem doing L1. Initially I was doing it everyday but I had to take a rest day here and there. L2 is much easier on the knees. What I did was rub it with A535 and did the modified exercises with the jumping jacks. It will get better when you give it rest and treat it. Keeping going....it will get better.

My right knee has been messed up too. My gym lady says its from all the jumping. I'd like to start over since I only completed levels 1 and 2 but its been like a month since i've done anything. My knee still bothers me a little so I'm just going to to stick with jumping jacks instead of all the jump ropes and knee raises and such. Or just do light marching to keep the heart rate up. And stick with elliptical for cardio.