Problem When VB save in DB

[sacramento]

Hi to all:

This peace of code put one value in DB:

 Dim con1 As New OleDb.OleDbConnection(String.Format("PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source = " & drive & IDempresa))
        Dim sSQL As String

        valorcolocardebito = FormatNumber(valorcolocardebito, 2)

        If valorcolocardebito = 0 Then
            valorcolocardebito = 0
        End If


        sSQL = "UPDATE balancetegeral SET numeroconta = @contaacolocar, "
        sSQL = sSQL & "mensaisdebito = @valorcolocardebito "
        sSQL = sSQL & "WHERE numeroconta = @contaacolocar"

        Dim command As New OleDb.OleDbCommand(sSQL, con1)

        With command.Parameters
            .AddWithValue("@contaacolocar", contaacolocar)

            If valorcolocardebito = 0 Then
                .AddWithValue("@mensaisdebito", DBNull.Value)
            Else
                .AddWithValue("@mensaisdebito", valorcolocardebito)
            End If
        End With

        con1.Open()
        command.ExecuteNonQuery()
        con1.Close()

I had run the code step by step and he do a strange,better, very strange thing...
The value puted in valorcolocardebito = 263.733,69 and when I confirm this value in DB i have 263.733,70...
More surprise is because he make this for an values and for other save very well...
This could be surealistic,but it is that I have and sincerely i don't know way this happen...

Can anyone give me an suggestion?

Thanks