Ausdruck in Kontext nicht definiert

Public Sub Optimiere()
Dim mySheet As Worksheet
Dim highestPriceDate As Date
Set mySheet = ActiveSheet
While WorksheetFunction.Min(mySheet.Range("J:J"))  0
highestPriceDate = findHighestPriceDate(mySheet.Range("F3:F8790"), 9, 1, 3, 8790)
Call populateLevels(mySheet.Range("A3:A8790"), highestPriceDate, 1, 4, 8, 10, 11, 9)
Wend
End Sub

Private Function findHighestPriceDate(DemandPrice As Range, HydroInputCol As Integer,  _
TimestampCol As Integer, startR As Long, endR As Long) As Date
Dim HighestPrice As Single
Dim HPRow As Long
Dim thisSheet As Worksheet
Dim r As Long
Dim c As Long
HighestPrice = 0
Set thisSheet = DemandPrice.Worksheet
c = DemandPrice.Column
For r = DemandPrice.Row To DemandPrice.Row + DemandPrice.Rows.Count - 1
If thisSheet.Cells(r, c) > HighestPrice And thisSheet.Cells(r, HydroInputCol) = "" Then
HighestPrice = thisSheet.Cells(r, c)
HPRow = r
End If
Next r
findHighestPriceDate = thisSheet.Cells(HPRow, TimestampCol)
End Function

Private Sub populateLevels(myRange As Range, dateToFind, TimestampCol, DemandCol,  _
availableCapacityCol, ResidualOptimizationCol, generatedMWhCol, HydroInputCol)
Dim r As Long
Dim mySheet As Worksheet
Dim myMin As Single
 r = myRange.Find(dateToFind).Row
Set mySheet = myRange.Worksheet
myMin = WorksheetFunction.Min(mySheet.Cells(r, DemandCol), mySheet.Cells(r,  _
availableCapacityCol), mySheet.Cells(r, ResidualOptimizationCol))
mySheet.Cells(r, generatedMWhCol) = myMin
mySheet.Cells(r, HydroInputCol) = myMin
End Sub