Issues Installing DIGITS on Linux 14.04

Hello people, i’m a new user of Linux and also to the field of deep learning. I was trying to install DIGITS as per the installation instructions, but I am having some issues. When i type “apt-get update” i get an error saying E: Could not open file …

Can someone please help me with this.

Could you please post the fully error messages?
It would be helpful to identify if they’re harmless messages.