Cannot download Mountain Lion

[#1]

I have the necessary software to be able to download Mountain Lion but when i go to the app store and try to download it i get the following message:  The product distribution file could not be verified. It may be damaged or was not signed.  Does anyone know what I should do next

[#2]

You can have a look here http://www.macworld.com/article/1164809/bugs_and_fixes_solving_mac_app_store_download_errors.html
There doesn't seem to be any one particular resolution. I've managed to download it fine on 3 macs.