I got an error keep on prompting telling me NullReferenceException when i run the pocketpc emulator to test my development. Can anyone tell me what's the problem. I will attach my code below as reference. Thanks

rivate Sub cmdConnect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdConnect.Click
        Dim frmSelector As New frmSelector
        Dim frmLoginMgmt As New frmLoginMgmt
        Dim conn As New SqlConnection
        Try
            conn.ConnectionString = "server=celeron; uid=James; password=something; database=LPL"
            conn.Open()
            Dim sql As SqlCommand
            sql.CommandText = "SELECT * FROM tbllogin WHERE username='txtusername.Text' AND password='txtpwd.text';"
            If sql.CommandText = True Then
                'If txtusername.Text = "admin" And txtpwd.Text = "admin" Then
                MessageBox.Show("Connection Established")
                frmSelector.Show()
            Else
                MessageBox.Show("Invalid Login Name or Password")
            End If

        Catch sqlex As SqlException
            Dim sqlError As SqlError
            For Each sqlError In sqlex.Errors
                MessageBox.Show(sqlError.Message)
            Next
        Catch ex As Exception
            MessageBox.Show(ex.Message)

        Finally
            If conn.State <> ConnectionState.Closed Then
                conn.Close()
            End If
        End Try

    End Sub
End Class