The update cannot be downloaded, as a "not found" error message occurs.
In the logfile, the following error message is found in the Control Messages: Update file: xxxx.tgz not found.
Check to see if the .tgz file format is being blocked or rejected by the firewall or virus scanner.
Also check in the firewall if the SMTP Content Type application/octetstream is blocked.
If so, unblock this action.