Hi Todd , Thanks for you soon answers
Precisely adding that line to the repositories files is where I'm having the message.
I have been trying removing and adding spaces and quotes , but same message return , its not able to fetch or connect to the HTTP.
So far what I have is a fresh install of Debian 7.11 , without Linux CNC , then the Preempt Rt kernel.
I have confirmed thru the uname -v , command.
Do I have to install a previous version of the Linux CNC , then upgrade ?
Im a little bit confused , Im not a Linux guy , but willing to learn , even though will take some time.
Is there any thing else I might try ? I don't want to go over a pre configured hard drive.
Thanks.