So as first idk if is a right place to post here about my problem  
here you go The codes ... .lua scrip  Resource in folder file  
lua code  
 
function ReplaceCar() 
txd = engineLoadTXD('buffalo.txd', 402) 
engineImportTXD(txd, 402) 
dff = engineLoadDFF('buffalo.dff', 402) 
engineReplaceModel(dff, 402) 
end 
addEventHandler( 'onClientResourceStart', getResourceRootElement(getThisResource()), ReplaceCar) 
  
 
Error ?  
here  
 
 attemp to call global "getThisResource" (a nil value)