Anywayz,
You CANNOT save ONLINE close-battle.net characters in ANY way. They are ALL saved on the server.
You CAN save single player characters. And what I think you are trying to say..well here goes.
Save your characters and maps to a floppy disk (or a different folder) when something bad happens REMOVE all your new files (characters, maps, w/e) and reload^*1 your characters and maps.
*1: You cannot just open a character file. Only the game reads it (or editing software ex: zonfire [which if you want I can give you link. its not hard to find
]
You have to replace the new/bad/corrupted files with the ones you saved on the floppy disk. By doing that just find what folders your characters are in and click and drag your backups in there. Overwrite and your done!