Loop error?

I need help with this program, i getting this error:

bios:140: vm error: java.lang.ArrayIndexOutOfBoundsException: 256

program check:

Spoiler

turtle.select(1)
if turtle.compare() == false then
turtle.select(2)
if turtle.compare() == false then
turtle.select(3)
if turtle.compare() == false then
turtle.select(4)
if turtle.compare() == false then
turtle.select(5)
if turtle.compare() == false then
turtle.select(6)
if turtle.compare() == false then
turtle.dig()
shell.run("turn")

end
else
shell.run("turn")

end
else
shell.run("turn")

end
else

shell.run("turn")

end
else
shell.run("turn")

end
else
shell.run("turn")
end

program turn:

Spoiler

if i==4 then
turtle.digDown()
turtle.down()
i = 1
shell.run("check")
else
i = i+1
turtle.turnRight()
shell.run("check")
end

Is there any reason you are using separate files and shell.run? Try moving them into the same file and using functions instead of shell.run

function turn()
  -- do stuff
end

function check()
  -- do stuff
  turn()
end

check()

Thank you, that helps alot but still the same error….before it was for 4 moves or so,with functions it is for 30 moves.
I need program that dig down to bedrock and mine only ores, so i compare 6 slots with materials i dont want….

Paste your code in code tags.

So formatting like indentation gets preserved. That thing in your original post is nearly impossible to read.

You're calling turn from check and check from turn. That will overflow the stack in short order if nothing stops one from calling another instance of the other at some point.