Error: Manifest data not found in archive

What does this mean?

PHP max_execution_time : 900s

Attempting to download remote file : https://www.dropbox.com/s/5wwjm1abh5snewl/snapshot-ehk-10152015.zip?dl=0

Processing archive: snapshot-ehk-10152015.zip?dl=0 (220.88kb)

Error: Manifest data not found in archive.

Snapshot import complete