Smell shouldn't have any effect on the fermenting beer. Gases are only supposed to be coming OUT of your fermenter. When you get a chance, you should bleach the heck out of the inside of the freezer, let it soak, rinse, repeat, then let it air out a few days.
After that, close it up for a week or two with a generous amount of baking soda in there.
Unless there was some really bad stuff in there like rotten meat, where the "juice" ran down behind the interior panels and got into the insulation, the above procedure should cure the problem. Not a quick fix though.