Update fail

So, today I did a clean install on Netrunner 14.04 Frontier, everything is good until I ran sudo apt-get update && sudo apt-get upgrade right after I logged in and I got this problem:

I installed synaptic to fix the problem, but it didn’t work. My source.list is empty, nothing in it.How can I solve this problem, I did nothing after the installation. Thank you.

The sources.list is broken. Try reinstalling the netrunner-apt-config package.
Normally it isn’t broken. Did you edit the sources.list or added a ppa with any graphical tool ?