You don't need to know where the SOL file is, Flash will take care of that when you retrieve your object. So you can retrieve what you saved and reset your movie to whatever state you like.

If you use SWF Studio you don't have to worry about SOL files etc, the data will be stored as part of the EXE file. That means you could give a copy of that EXE file to someone else and they would start at the same place too. You can't do that with SOL files