The verification process fails if the FIrmware archive is modified in any way. This happens a lot when the network connection is unstable and the update file downloaded gets corrupted in the process. You can try by downloading the file from a more stable network connection.
Another source of this kind of problems could be a virus tampering any file downloaded to your PC. Try to change to another PC, download the Firmware again and update from file. Below you will find the firmware download link.
If the problem persists we recommend you to get in contact with your sales representative and provide more information about the issue.