New transaction is not allowed

See more:

VB

I My VB.net application , saving function an error occurred when

transaction = roConform.BeginTransaction()

Error:
New transaction is not allowed because there are other threads running in the session

Code::

Private Sub tolSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tolSave.Click
        Call SaveData()
 End Sub

 Private Sub SaveData()
        Dim dsLogin As DataSet
        Dim amount As Double
        Dim credit As Boolean        
        Try
            If (UserPower = 1) Then
                If SaveFlag = False Then

                    transaction = roConform.BeginTransaction()
                    dsLogin = clsBrand.AddMember(roConform, transaction, 1, 0, txtSerialNo.Text, Format(dtpAdmitDate.Value, "dd/MMM/yyyy"), txtAngamNo.Text, txtName.Text, txtSirname.Text, txtHouse.Text, txtPlace.Text, txtaddress.Text, txtpostoffice.Text, cmbdistrict.Text, amount, credit, txtRemarks.Text, cmbunit.Text, txtph.Text, txtmob.Text, txtnameeng.Text)
                    transaction.Commit()
                    MsgBox("Successfully Saved !")
                ElseIf SaveFlag = True Then
                    transaction = roConform.BeginTransaction()
                    dsLogin = clsBrand.AddMember(roConform, transaction, 2, rowid, txtSerialNo.Text, Format(dtpAdmitDate.Value, "dd/MMM/yyyy"), txtAngamNo.Text, txtName.Text, txtSirname.Text, txtHouse.Text, txtPlace.Text, txtaddress.Text, txtpostoffice.Text, cmbdistrict.Text, amount, credit, txtRemarks.Text, cmbunit.Text, txtph.Text, txtmob.Text, txtnameeng.Text)
                    transaction.Commit()
                    MsgBox("Successfully Updated !")
                End If
            End If        
        Catch ex As Exception
            transaction.Rollback()
            MsgBox(ex.Message)
        End Try
    End Sub

How to resolve it