It looks like the snapshot .vmdk files (files with "...-00000x..." in their names) have been deleted manually!?
According to the file list there are no snapshot files which you can revert to. However the .vmsn (snapshot state) and .vmsd (snapshot descriptor) files still exist which most likely cause the error message you see. What you may do in this case is to delete the .vmsn and .vmsd files from the datastore and reload the VM.
André