heddington on "[Plugin: WP Backitup] Restoration file could not be unzipped."

Hi,

A recent update of Woocommerce plugin has given a problem with my store pages.
I therefore wish to revert to the state I had before updating.

When I try to restore to a backup zip I get the following message

Error: Your restoration file could not be unzipped.

and the indicator just keeps spinning until I go to another dashboard page.

WP version 3.8.1,
WP Backup Version 1.5.5

Thanks

https://wordpress.org/plugins/wp-backitup/