{SOLVED} turtle.inspectDown() gives error farm:28: attempt to call nil

I am using the computercraft mod in the Feed the Beast modpack, TechWorld2.
Every time I try to run my code in the file farm, I get error farm:28: attempt to call nil.

if turtle.detectDown() then
  local suc, t = turtle.inspectDown()
  if suc and t.name == "minecraft:wheat" and t.metadata == 7 then
	turtle.digDown()
	...
  end
end

Line 28 is the line

local suc, t = turtle.inspectDown()

Am I doing something completely wrong here? I've stared at this for about an hour and can't see the problem.

What version of ComputerCraft are you using?

Computercraft version 1.58 is what is on the modpack for techworld 2 in feed the beast

Well that would explain it. Turtles did not have that function in that version.

Well, now I feel dumb. Thank you very much, I will try to update my mod pack asap!