Is savegame number 7 in the savegame folder available?
Do you have specified a savedir folder?
*)But both should make no problems. There would be a beep.

First I thought it is maybe only the savegame. The error message 1513: missing entity, try to use an empty pointer, or a DEP (data execution prevention) problem, or a damaged sound, model or image.

I think it is a missing entity or something like that, because you have saved the game without Levels. So all the entitys are not saved, but you load the savegame with the actions for that missing entity.