OleDb Transaction

Hi,

When I try to update different tables using Transaction I get the following error;

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:
Line 335:                    InTrans.Rollback()

update sub;

Dim InCommand As Data.OleDb.OleDbCommand = Con.CreateCommand()
Dim InTrans As Data.OleDb.OleDbTransaction

            If Con.State <> ConnectionState.Open Then
                Con.Open()
            End If

            Try
                rdr = cmd1.ExecuteReader

                If rdr.Read Then
                    NewTotalIN = rdr.Item("TotalIN")
                    If NewTotalIN = "" Or IsDBNull(NewTotalIN) Or Not IsNumeric(NewTotalIN) Then NewTotalIN = 0
                    Response.Write(NewTotalIN)
                End If
                rdr.Close()

                rdr = cmd2.ExecuteReader
                If rdr.Read Then
                    sum1 = rdr.Item("TotalOUT")
                    If sum1 = "" Or IsDBNull(sum1) Or Not IsNumeric(sum1) Then sum1 = 0
                End If
                rdr.Close()

                rdr = cmd3.ExecuteReader
                If rdr.Read Then
                    sum2 = rdr.Item("TotalOUT2")
                    If sum2 = "" Or IsDBNull(sum2) Or Not IsNumeric(sum2) Then sum2 = 0
                End If
                rdr.Close()

                rdr = cmd4.ExecuteReader
                If rdr.Read Then
                    txtROL = rdr.Item("ROL")
                    If txtROL = "" Or IsDBNull(txtROL) Or Not IsNumeric(txtROL) Then txtROL = 0
                End If
                rdr.Close()

                rdr = cmd5.ExecuteReader
                If rdr.Read Then
                    txtOldQtyIN = rdr.Item("QtyIn")
                    If txtOldQtyIN = "" Or IsDBNull(txtOldQtyIN) Or Not IsNumeric(txtOldQtyIN) Then txtOldQtyIN = 0
                End If
                rdr.Close()

                If ((NewTotalIN) - (txtOldQtyIN) + txtQtyIn) < ((sum1) + ((sum2) + txtROL)) Then
                    Response.Write("<script language='JavaScript'>alert('You cannot update.');</script>")
                    found = 1
                End If

                If found = 0 Then

                    InTrans = Con.BeginTransaction()
                    InCommand.Connection = Con
                    InCommand.Transaction = InTrans

                    InCommand.CommandText = UpdateStr1
                    InCommand.ExecuteNonQuery()

                    InCommand.CommandText = UpdateStr2
                    InCommand.ExecuteNonQuery()

                    Response.Write("<script language='JavaScript'>alert('Spare Parts IN updated successfully!');</script>")

                        InTrans.Commit()
                End If

            Catch ex1 As Exception
                Try
                    InTrans.Rollback()
                Catch ex As OleDbException
                    If Not InTrans.Connection Is Nothing Then
                        Console.WriteLine("An exception of type " & ex.GetType().ToString & _
                                          " was encountered while attempting to roll back the transaction.")
                    End If
                End Try

                'Catch ex As OleDbException
                Console.WriteLine("An exception of type " & e.GetType().ToString() & _
                            "was encountered while inserting the data.")
                Console.WriteLine("Neither record was written to database.")
            Finally
                Con.Close()
            End Try

can anyone pls. help me to solve the problem?

ayha