Error on import with snapshot?

Hi,

I have created a new WP install. Installed Snapshot.

Unloaded copy of snapshot from demo of website.

Clicked on import on snapshot.

And the import finds the file.

But gives this error:
"Processing archive: snapshot-1381759897-131022-075323-3928103c.zip (0b)
Error: Manifest data not found in archive"

I can see the snapshot in the folder, and it is 14mb. Certainly not 0KB

what does this mean, and how can i fix?

Regards

Rob