Ja, hast recht habe ich beseitigt. Der Fehler bleibt jedoch, leider. Hier mal der ganze Code: 

Sub LeseArtiekNummern()
    Dim wbAktiv As Workbook         'Variable Ziel Workbook
    Dim wbAL010 As Workbook      'Variable Quelle Workbook
    Dim wbSA021 As Workbook
    Dim wbSLM0003 As Workbook
    Dim wbSLM0022 As Workbook
    Dim intLastQuelle As Integer
    Dim IntLastAktiv As Integer
    
    Set wbAktiv = ActiveWorkbook                            'bestimmung Ziel Workbook
    Application.EnableEvents = False
    Set wbAL010 = Workbooks.Open(Sheets("StartPage").PfadAL010.Value)      'bestimmung/öffnen Quell 1
    Application.EnableEvents = True
    intLastQuelle = wbAL010.Sheets(2).UsedRange.Rows.Count   'ermittlung Zeilen in Quell Datei
    
   With wbAL010.Sheets(2) 'Einige Spalten aus der ersten Quelle werden entnommen
        .Cells(2, 1).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 1).EntireColumn.Insert
        
        .Cells(2, 2).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 2).EntireColumn.Insert
        
        .Cells(2, 3).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 3).EntireColumn.Insert
        
        .Cells(2, 4).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 4).EntireColumn.Insert
        
        .Cells(2, 6).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 5).EntireColumn.Insert
        
        .Cells(2, 20).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 6).EntireColumn.Insert
        ' 7 Last Week
        ' 8 This Week
        .Cells(2, 11).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 9).EntireColumn.Insert
        ' SGF 10
        .Cells(2, 26).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 11).EntireColumn.Insert
        
        .Cells(2, 25).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 12).EntireColumn.Insert
        
        .Cells(2, 35).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 13).EntireColumn.Insert
        
        .Cells(2, 37).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 14).EntireColumn.Insert
        
        .Cells(2, 38).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 15).EntireColumn.Insert
        
        ' 16 RTO
        ' 17 RTR
        .Cells(2, 12).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 18).EntireColumn.Insert
        
        .Cells(2, 18).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 19).EntireColumn.Insert
        
        .Cells(2, 33).EntireColumn.Copy
        wbAktiv.Sheets("Data").Cells(2, 20).EntireColumn.Insert
        
   End With
        
   Application.CutCopyMode = False
   wbAL010.Close SaveChanges = False
   
   Application.EnableEvents = False
    Set wbSA021 = Workbooks.Open(Sheets("StartPage").PfadSA021.Value) 'bestimmung/öffnung Quell 2
    Application.EnableEvents = True
    intLastQuelle = wbSA021.Sheets(2).UsedRange.Rows.Count
    IntLastAktiv = wbAktiv.Sheets("Data").UsedRange.Rows.Count
    
    For x = 2 To IntLastAktiv
    Debug.Print wbAktiv.Sheets("Data").Cells(x, 3).Value
    ' Hier entseht wohl der Fehler
        Workbooks("Workliste Einzeiler.xlms").Sheets("data").Cells(x, 7) = Application.WorksheetFunction.VLookup(Workbooks("Workliste Einzeiler.xlms").Sheets("Data").Cells(x, 3).Value, Workbooks("SA021.xlsm").Sheets(2).Range("C:Q"), 15, False)
    Next x
    
    
   
   wbSA021.Close SaveChanges = False
   ' Set wbSLM0003 = Workbooks.Open(Sheets("StartPage").PfadSlm0003.Value)
   ' Set wbSLM0022 = Workbooks.Open(Sheets("StartPage").PfadSlm0022.Value)
    
    
End Sub