For at least one necessary perameter was no value given

 Dim con As New OleDbConnection
        Dim cmd As New OleDbCommand
        Dim reader As OleDbDataReader
        Dim out As String = ""
        con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;" & "Data Source=<here was the Path to my File, but i have blanked it>;" & "Persist Security Info=False"
        cmd.Connection = con
        cmd.CommandText = "SELECT Doktoren.Bezeichnung, Doktoren.Sitze FROM ( Verteilung INNER JOIN Doktoren ON Doktoren.ID=Verteilung.Dr_ID ) INNER JOIN Dienste ON Dienste.ID=Verteilung.Dienst_ID ORDER BY Dienste.Zeit"
        Try
            con.Open()
            reader = cmd.ExecuteReader(CommandBehavior.Default)
            Do While reader.Read()
                out += reader("bezeichnung") & " # " & reader("Dr_ID") & " # " & reader("sitze") & vbCrLf
            Loop
            reader.Close()
            con.Close()
            Console.Write(out)
        Catch ex As Exception

        End Try

I Get the Error Message from the title, when executing cmd.ExecuteReader(...)

Thanks in Advance

BLDL