I have an Arduino Due I'd like to start using. I've been using Unos, Megas etc no problem. The newer IDEs have removed the Due support. I've been trying to install Due support through the Board Manager, but when I open the Boards Manager, I get :

Error downloading http://downloads.arduino.cc/packages/package_index.json

and when I try to install Due support, I get :

Error downloading http://downloads.arduino.cc/cores/sam-1.6.4.tar.bz2

I understand I may be behind proxies, but in IDE version 1.6.5, that has been removed from the Preferences, so I can't change that. I have tried to allow the IDE past the Windows Firefall, but that has not changed anything.

I have manually downloaded sam-1.6.4.tar.bz2 and extracted the contents to C:\Arduino\arduino-1.6.5\hardware\arduino\sam (I had to manually create the sam folder). With this, I can see the options of Arduino Due Native USB Port and Arduino Due Programming Port when selecting the board, and when I look for it in the Ports, it can recognise the board at the port (eg "COM5 (Arduino Due (Programming Port))" ). When I try to compile anything, I get the error message :

Cannot run program "{runtime.tools.arm-none-eabi-gcc.path}\bin\arm-none-eabi-g++" (in directory "."): CreateProcess error=2, The system cannot find the file specified

Any other idea as to how I can install the Due? Is there an option for a manual installation? The same happens with Libraries Manager (I don't get a connection), so I guess, the same can be applied to that.