Error

[AlphaMark]

Why wont this work, The error is: Bad argument @ 'triggerClientEvent' [Expected element at argument 2, got nill]

 function SweepEnter(theVehicle, seat, jacked) 
    local id = getElementModel ( theVehicle ) 
    if id == 574 then 
    outputChatBox("You are now sweeping!", thePlayer, 255, 0, 0) 
    triggerClientEvent("SweepRoute", thePlayer) 
    end 
end 

[TAPL]

What is the event?

[AlphaMark]

function SweepRoute() 
local currentIndex = 1 
local route = 
    { 
        { 0, 0, 0 }, 
        { 0, 0, 1 }, 
        { 0, 0, 2 }, 
        { 0, 0, 3 }, 
        { 0, 0, 4 }, 
    } 
marker = createMarker ( unpack ( route [ currentIndex ] ) ) 
  
addEventHandler ( "onMarkerHit", root, 
    function ( ) 
        if ( source == marker ) then 
            currentIndex = ( currentIndex + 1 ) 
            destroyElement ( marker ) 
            marker = nil 
            marker = createMarker ( unpack ( route [ currentIndex ] ) ) 
        end 
    end 
) 
end 

[AlphaMark]

function SweepRoute() 
local currentIndex = 1 
local route = 
    { 
        { 0, 0, 0 }, 
        { 0, 0, 1 }, 
        { 0, 0, 2 }, 
        { 0, 0, 3 }, 
        { 0, 0, 4 }, 
    } 
marker = createMarker ( unpack ( route [ currentIndex ] ) ) 
  
addEventHandler ( "onMarkerHit", root, 
    function ( ) 
        if ( source == marker ) then 
            currentIndex = ( currentIndex + 1 ) 
            destroyElement ( marker ) 
            marker = nil 
            marker = createMarker ( unpack ( route [ currentIndex ] ) ) 
        end 
    end 
) 
end 

[TAPL]

^^ Is this client side or server side?

And btw, i was asking what the event used with this code:

And why you need the trigger.

function SweepEnter(theVehicle, seat, jacked) 
    local id = getElementModel ( theVehicle ) 
    if id == 574 then 
    outputChatBox("You are now sweeping!", thePlayer, 255, 0, 0) 
    triggerClientEvent("SweepRoute", thePlayer) 
    end 
end 

Probably it's source not thePlayer.