I'm half sure that just looking at dmesg would suffice, as the error to execute some commands in rc should be logged there.
Otherwise try the answer to the question here to set up a log file and then reboot http://askubuntu.com/questions/434242/where-is-log-file-from-rc-local
Otherwise try the answer to the question here to set up a log file and then reboot http://askubuntu.com/questions/434242/where-is-log-file-from-rc-local
