Attempt to to index ? (a nil value)

I am new to computercraft only having watched and read a few tutorials. I am trying to make a programs that fills up three buckets that are in different slots in the turtle.The name of the progran is "fill". Here is the code;

while true do
turtle.select(1)
turtle.place()
turtle.select(2)
turtle.place()
turtle.select(3)
turtle.place()
sleep(2)
end

The error I receive when attempting to run the code is;
fill:4: attempt to index ? (a nil value)

Split into new topic.

Are you sure that that is the exact code you're using to cause that error?

Works fine…
sure you're making a normal program?

Double checked a found a spelling mistake in the code. Sorry about this.