Laufzeitfehler 438

Sub gaeb_export()
Application.ScreenUpdating = False
Dim sucheZeile As String
Dim Stamm_exp As String
Dim varFile_exp As Variant
Dim varName_exp As Variant
Dim Blatt_exp As String
Dim oznum As String
Dim Rowcalc As String
'        On Error GoTo Err
Stamm_exp = ActiveWorkbook.Name
varFile_exp = Application.GetOpenFilename("Excel Files (*.xlsx), *.xlsx", , "XLSx",  _
_
"Auswahl", _
False)
If TypeName(varFile_exp) Like "Boolean" Then
MsgBox "Keine Datei gewählt!", vbInformation
Exit Sub
Else
varName_exp = Right$(varFile_exp, Len(varFile_exp) - InStrRev(varFile_exp, "\"))
'            lstRow = Workbooks(Stamm_exp).Sheets("Kalkulation").Cells(Rows.Count, 4).End(xlUp). _
_
Row
Check_Rowcalc:
If Workbooks(Stamm_exp).Cells(Rowcalc, 3).Value = "" Then
Rowcalc = Rowcalc + 1
GoTo Check_Rowcalc
Else: oznum = Workbooks(Stamm_exp).Cells(Rowcalc, 3)
End If
Workbooks.Open varFile_exp
sucheZeile = Workbooks(varName_exp).Sheets("GAEB_Konverter_LV").Columns("B:B").Find( _
_
What:="Berta", After:=Cells(2, 2), LookIn:=xlFormulas, _
LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, _
MatchCase:=False, SearchFormat:=False).Row
Range("BI1").Value = sucheZeile
End If
Exit Sub
Err:
Call MsgBox("FEHLER" _
& vbCrLf & "Bitte wenden Sie sich an den Administrator" _
, vbExclamation, "Fehler")
End Sub