Hi, I’m not familiar with the terminal environment or Linux, i followed the instructions to install…
Ibraheem abu hamdeh

Thank you for your response! I think, your issue related with hostname(u should avoid using hyphen in your hostname, this topic — http://askubuntu.com/questions/59458/error-message-when-i-run-sudo-unable-to-resolve-host-none will help you. Just change your hostname. Contact me if this does not solve the problem.