How to handle System.Runtime.InteropServices.COMException (0x800A03EC): Exception from HRESULT: 0x800A03EC.

Hi,
Getting an error when trying to count rows in excel sheet by this function
Public Function GetColumnRowCount(ByVal col As Integer, ByVal xlWorksheet As Object) As Integer
             Return xlWorksheet.Cells(xlWorksheet.Rows.Count, col).End(-4162).Row
           
    End Function


Created excel application as follows:
   xlApp = CreateObject("Excel.Application")
                        FlagGetObj = True
                        xlApp.visible = False
                        xlApp.displayalerts = False
                        xlWB = xlApp.Workbooks.Open(workbook)    ' change the name of the sheet you require
                        Application.DoEvents()
                        xlWS = xlWB.Worksheets(ExcelSheetName)
                        xlWS.Activate()
                        xlApp.visible = True
                        k = GetColumnRowCount(col, xlWS) 'get number of records in excel sheet