I had exactly the same ER07 code on my Hotpoint oven. The knobs on the oven were too hot to touch. When I turned it off and let it cool down it would work again. This normally only happened when I had the oven on a high temperature.
I called Hotpoint and they were no help and said the code error reasons were not something they gave out!?!
It turned out it was the seal on the door letting out the heat. The seal on the door can be removed and put in the dishwasher which is what I did months ago. I must have put it back on incorrectly. I removed it, put it back on again which must have sealed it better, and voila no problem since!
Perhaps ER07 is a code used my many manufacturers for when the display panel overheats.
Hope this is a solution for you.
Dan Williams
June 2008