Some users have reported that the installation process is interrupted when they try to install Windows OS on their hard disk. As soon as they press the Install now button in the Windows Setup process, ...
Hmm. So you're using the Partition tab in Disk Utility, and you're selecting GPT in the Options dialog, and you set one partition to be FAT and the other to be HFS+ (so that neither is unformatted ...
The default Windows disk tooling is inadequate, but thankfully, GParted exists ...