Well I gave the grill another try today.
I found an outlet that wasn't GFI and tried it there. This time it worked fine and heated up nicely. The only thing I noticed was that one area of the cord got quite warm. I wonder if there is a weak spot in it and that was causing the GFI outlets to pop. It appears to be a fairly common cord so I think I can get a replacement at an electrical supply store.
I'm really excited that there isn't any major problems with it. Now it's time to order a new Zavdle for it and get on with the second "R".