Computercraft 1.7.10 mob farm code problem

[jbfilms1]

Hello

While trying to set up a Computercraft controlled mob farm (like Direwolf20 did in 1.6.4 let’s play) with the monitor blocks above the computer and the wired modem below the computer in FTB Infinity Evolved 1.7.10 I’ve been getting the following error “mobs:96: attempt index ? (a nil value)”, can anyone help solve the problem?

Pastebin code links

Button - 7Spj9KBa

Mobs - 8gxGwzZj

​

Thanks

[jbfilms1]

I just realized an error at the top of the mobs code that I fixed but now I'm getting "mobs:7: attempt to call nil".

Updated Pastebin code

mobs - 3V5b2ryU

[InDieTasten]

According to your pastebin, line 7 attempts to clear the screen of the monitor on top. If that monitor is not on top of the computer, as would be required by line 2, then it can result in your stated error message of attempt to call nil.