I decided to give it a try on a Windows 7 pc , basically you need to follow the tutorial to install Boot2Docker which will is simple enough in terms of just being an exe that will kick start a stripped down Linux instance on your Windows pc or Mac .
The first thing you need to do is try out this simple command:
docker run hello-world
The picture below explains syntax within the commands:
A simple googling provided a rapid answer that the problem had to do with Cisco Connect Anywhere , if you have it installed either you need to exit it ( and close from system tray ) or you can follow the instructions from this stackoverflow query:
Sure enough once Cisco Connect Anywhere was closed i was able to download the image.