Updating orca error

[Linux for blind general discussion]

Hello list,

I was trying to update orca using mark Christopher gillen instructions. I am using ubuntu mate and after following the instructions where he says to type sudo apt-get build-dep orca i got the following error.

You must put some ‘source’ URIs in your sources.list . What is wrong , how do i fix this problem? Also I've never had any problems up until now. 
 

 
Michael maslo