So did you do gem install charlock_holmes ? though I don't think it is being used anywhere in
github.com/concord-consortium/lab. So please take a look again if you've cloned the correct repo. Still run that command if it says.
Also, do verify if your version of rvm and ruby is the correct one, 2.0.0-p247 or earlier patches are the one's required for lab's repo. Though I see your version of ruby is probably the correct one.
Also, have a look if you get any broken packages when doing sudo apt-get update because that causes problems when we run ruby and rvm commands.
Run a "bundle install" before running the make so that the important gems get installed beforehand.
I hope one of this works. :)