I currently have a Apple Developer Account and am trying to install the beta on my iPod Touch 5th Gen. I download it and unable to properly mount it due to it saying 'invalid checksum'.
Was the iPod jail broken? I'm googling and it seems to bring up discussions pertaining to jail broken devices.
Edit: did you try re downloading the file? Other answers included incomplete download files.
Thanks for the reply. Apparently when you download the file with Chrome you will continue to get the invalid checksum. The first time I downloaded it via Safari, everything was a success!