Duplicate error: expected wave name

#pragma rtGlobals=1		// Use modern global access method.

//-----------------  Menu Code  -----------------
Menu "Intensidad Trafico Loader"
	"Intensidad Trafico Loader",  TraficoLoader()
End


Function TraficoLoader()
// This function should load files (with the edning ".csv") from the Intensidad Trafico Ayto. Madrid
	string fileList, tempfile
	variable iFile, numFile

	NewPath /M="Choose folder containing Intensidad Trafico Data files (ending '.csv')" RawDataPath 
//	Index Directory
	fileList = IndexedFile(RawDataPath, -1, ".csv")
	print fileList
	
	numFile  = itemsinlist(fileList)

	if(datafolderexists("Intensidad_Trafico"))
		setdatafolder Intensidad_Trafico
	else
		newdatafolder /S Intensidad_Trafico
	endif

	For(iFile=0; iFile < numFile; iFile+=1)
		tempfile = stringfromlist(iFile, FileList)
		
		TraficoLoadDataFiles(tempfile)
	Endfor
End function

// -------------------------- -------------------------- -------------------------- --------------------------
	
Function TraficoLoadDataFiles(tempfile)
	string tempfile
	string ListOfWaves, WaveNm, NewNames
	variable numWaves, iWave
		
		// Names for the waves in the file
		NewNames = "idelem;fecha;identif;tipo_elem;tipo;intensidad;"
		NewNames += "ocupacion;carga;vmed;error;periodo_integracion;"
		
		if(!waveexists(idelem))
			LoadWave/J/D/A/W/B="C=1; F=8; F=-2; C=1; F=-2; C=1; C=1; C=1; C=1; F=-2; C=1;"/V={";","",1,0}/P=RawDataPath tempfile
			
			//rename the waves
			ListOfWaves = WaveList("wave*",";","")
			NumWaves = ItemsInList(NewNames)

			For(iWave=0; iWave<NumWaves; iWave+=1)
				wave wv1 = $stringfromlist(iWave, ListOfWaves)
				duplicate /O wv1 $stringfromlist(iWave, NewNames)
				killwaves /Z $stringfromlist(iWave, ListOfWaves)
			Endfor

			setdatafolder Intensidad_Trafico

		// If waves already exist, load into temp folder, then concatenate and delete folder
		else	
			newdatafolder /O/S temp
			LoadWave/J/D/A/W/B="C=1; F=8; F=-2; C=1; F=-2; C=1; C=1; C=1; C=1; F=-2; C=1;"/V={";","",1,0}/P=RawDataPath tempfile

			//rename the waves
			ListOfWaves = WaveList("wave*",";","")
			NumWaves = ItemsInList(NewNames)

			For(iWave=0; iWave<NumWaves; iWave+=1)
				wave wv1 = $stringfromlist(iWave, ListOfWaves)
				duplicate /O wv1 $stringfromlist(iWave, NewNames)
				killwaves /Z $stringfromlist(iWave, ListOfWaves)
			Endfor


			// Concatenate the waves
			numWaves = itemsinlist(NewNames)
			For(iWave=0; iWave < NumWaves; iWave +=1)
				WaveNm = stringfromlist(iWave, NewNames)
				wave TmpWv1 = $WaveNm
				wave TmpWv2 = ::$WaveNm
				concatenate {TmpWv1}, TmpWv2
			Endfor
			
			setdatafolder Intensidad_Trafico
			killdatafolder /Z temp
			
			// Sortwaves
			wave TempWv = $"idelem"
			Make /O/N=(numpnts(TempWv)) SortKey
			MakeIndex TempWv, SortKey
			for(iWave=0; iWave < numWaves; iWave +=1)
				WaveNm = stringfromlist(iWave, NewNames)
				wave TmpWv1 = $WaveNm
				IndexSort SortKey TmpWv1
			endfor			
			killwaves /Z  SortKey
			setdatafolder Intensidad_Trafico
		endif	
End function