MobSpwan:19: attempt to call nil

this is my code
and i have this problem "MobSpwan:19: attempt to call nil"

os.loadAPI("Button")
m = peripheral.wrap("top")
m.clear()
local lightsOn = false

function toggleSpawners()
rednet.open("left")
if lightsOn then
print("Turning the lights ON")
rednet.broadcast("lightsON")
else
print("Turning the lights OFF")
rednet.broadcast("lightsOFF")
end
rednet.close("left")
end

function fillTable()
Button.setTable("Lights",spawnersOn,10,20,3,5)
Button.screen()
end

function getClick()
event,side,x,y = os.pullEvent("monitor_touch")
Button.checkxy(x,y)
end

function spawnersOn()
Button.toggleButton("Lights")
rednet.open("left")
lightsON = not lightsOn
toggleSpawners()
end

fillTable()
Button.heading("Mod Farm")
Button.label(1,4,"Lights")
toggleSpawners()
while true do
getClick()
end

Button.setTable is nil. Are you defining the global 'setTable' function in the Button API? Posting the code of all relevant files (i.e. including "Button") is more likely to fix your problem, and please use the code tag (

) around code as it makes it so much more readable.

I assume you actually have the file "button" on the computer you are running this on.

I can't remember, but I think os.loadAPI is case sensitive, try 'button', instead of 'Button', if that's what the file is named.