[TEKKIT 1.52][CC 1.5.3][SMP]turtle.place() fails

--[[ Simple lumberjack program for the wiki.  Assumes the turtle is in the
bottom left corner of a 10 ahead and 3 to the right area of clear dirt or
grass.  Also, only works for oak saplings, since they can grow next to each
other. ]]--
local saplings = 1 -- the slot where the saplings are
turtle.select(saplings) -- select the saplings
while turtle.getItemCount(saplings) > 0 do -- while more saplings in inventory
for i = 1, 8 do -- plant 8 saplings in a row
turtle.turnRight()
if not turtle.compare() then -- if not a sapling, then a tree grew
turtle.dig()
turtle.forward()
while turtle.detectUp() do -- dig tree out
turtle.digUp()
turtle.up()
end
while not turtle.detectDown() do -- back down to ground
turtle.down()
end
turtle.back()
turtle.place() -- put down new sapling
end
turtle.turnLeft()
turtle.forward()
end
-- turn around and line up for next pass
turtle.turnRight()
turtle.forward()
turtle.forward()
turtle.turnRight()
turtle.forward()
os.sleep(30) -- sleep for 30 seconds to allow trees to grow
end