Error With Big Reactors Display Program [Please Help!]

I created this program to display information taken from a big reactor on startup, but I get an error: startup:4: attempt to index ? (a nil value)
Can anyone tell me what I need to change about the program? If you need to know anything else I can tell you. Please Help!

Code:
http://pastebin.com/xL2cnaR5

Is the monitor that you've connected via wired network labeled monitor_5? If not, you'll need to change the line that wraps that networked monitor.

-Removed, realized what I posted was irrelavent

Yay! That was the issue. I don't know how I missed that, Thank you so much! :D/>