import from excel error in datagridview

'ofdImport.Filter = "Excel Files (*.xls)|*.xls"
       ofdImport.FileName = ""
       If ofdImport.ShowDialog(Me) = Windows.Forms.DialogResult.Cancel Then

           Exit Sub

       End If
       txtPath.Text = ofdImport.FileName
       If txtPath.Text <> "" Then
           chkItemList.Visible = True
           dgvImportData.Visible = True
           pnlDataMsg.Visible = False
           dgvImportData.Columns.Clear()
           chkItemList.Items.Clear()
           Try

               Dim conExcel As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" & txtPath.Text & " '; Extended Properties=Excel 8.0;")
               Dim excelSelect As New OleDbCommand
               Dim excelAdp As New OleDbDataAdapter
               Dim excelSchemaDt As DataTable
               Dim dset As New DataSet

               If conExcel.State Then conExcel.Close()
               conExcel.Open()
               excelSelect.Connection = conExcel
               excelSchemaDt = conExcel.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, Nothing)
               Dim sheetName As String = excelSchemaDt.Rows(0)("TABLE_NAME").ToString()

               excelSelect.CommandText = "select * from [" & sheetName & "] "
               excelAdp.SelectCommand = excelSelect
               excelAdp.TableMappings.Add("Table", "TestTable")
               excelAdp.Fill(dset)
               dgvImportData.DataSource = dset.Tables(0)
               Dim i As Integer
               Dim q(dgvImportData.Columns.Count()) As String
               For i = 0 To (dgvImportData.Columns.Count - 1)
                   q(i) = (dgvImportData.Columns(i).HeaderText.ToString())

               Next i
               conExcel.Close()

               i = 0
               Dim a As String = ""
               'Dim q(frmImportWizard.gridImport.Columns.Count()) As String
               For i = 0 To dgvImportData.Columns.Count - 1
                   a = dgvImportData.Columns(i).HeaderText.ToString()
                   'CheckedListBox1.Items.Add(a)
                   chkItemList.Items.Add(a)
               Next i
               chkAll.Visible = True
               chkAll.Checked = False
               lblColumnData.Visible = True
           Catch ex As Exception
               'MsgBox(ex.Message, MsgBoxStyle.Information)
           End Try


       End If