You might also try:
(Yes, it is "| less", not "less". [Boring/technical explanation about to come. Skip the rest of this parenthesis if it gets too technical/boring.]This is called a pipeline, where you can pipe functions to others. The less command uses lesspipe.) so you can scroll down (with the up/down keyboard buttons, as the command "| less" does not use scrollbars ).
cat -n /etc/apt/sources.list | less
Also post any output (what text comes up after running the command) with [CODE][/CODE] tags:
([CODE]This text is in code tags[/CODE])
This text is in code tags
Or you could do pastebinit /etc/apt/souces.list and indicate the url.