If you have installed a previous version of the firmware upgrade, you may still need to manually uninstall the old files.
To do this:
Go to Control Panel --> Programs and Features --> UpgradeFirmware_V..... --> Uninstall
After uninstalling old versions of the firmware, try to download the firmware again.
If the download is still unsuccessful, please send an email to firstname.lastname@example.org to open a new support ticket for assistance.