Primeiro
Tente isto:
- Abra o Internet Explorer (Sim, o Internet Explorer)
- Cole este link no IE e escolha Executar.
link
Introduction
I have had a similar problem: after 75% of the file was downloaded, it
just got stuck. Then 5 minutes later or so, I've received the exact
same error message you did. How I've fixed it
As Geogrgios mentioned above, you need to add an exception to the
firewall.
Go to "Control Panel" and click on "System and Security" (make sure that "View by:" is set to "Category" and not to "Large icons" or "Small icons").
Choose Windows Firewall (the second option in the right menu). Then, "Allow a program or a feature through Windows Firewall" in the
left menu will be displayed, please click on it.
Click on "Change settings" to add exceptions.
Click on "Allow another program ..", which has gotten enabled, and in the new window click on "Browse..".
Choose the "GithubSetup.exe" file, press "Open" and then "Add" and "OK".
Run "GithubSetup.exe" and hope for the best.
Better instructions (with screenshots) can be found here
De: link
EDITAR
Tente instalar o .Net Framework 4.5 e tente novamente