If you open up an AS save file in a word processing program you will see it is a text file. Your file only contains 376k bytes of the same non letter. In other words it cant be save by me.
Is it possible that you saved something else over top of it by mistake? I've actually done that before. Accidentally clicked on a file in the save window when saving a different programs file. It picked up the name and extension of a totally different file and I replaced it.
Could it be that the upload to where the file is being hosted got corrupted?