appointment.RecurrenceRule = new RecurrenceRule(Pattern); ERROR

[ITA]

Hi,

i'm frustrated :-(
For me it's unpossible to add Patterns to an Appointment. The code above shows how i create my Pattern Objekt and how
i add this to my Appointment!

var Pattern = new RecurrencePattern();

Pattern.Frequency = Frequency_v;
Pattern.DayOrdinal = DayOrdinal_i;
Pattern.DaysOfWeekMask = DaysofWeekMask_v;
Pattern.FirstDayOfWeek = FirstDayofWeek_d;
Pattern.Frequency = Frequency_v;
Pattern.Interval = Convert.ToInt32(tasks_dr.Field<Int64>("Interval"));
Pattern.MaxOccurrences = Convert.ToInt32(tasks_dr.Field<Int64>("MaxOccurrences"));
Pattern.MonthOfYear = Convert.ToInt32(tasks_dr.Field<Int64>("MonthofYear"));
Pattern.DayOfMonth = Convert.ToInt32(tasks_dr.Field<Int64>("DayofMonth"));

System.DateTime? RecursUntil_d;
if (tasks_dr.Field<String>("RecursUntil") != "")
    {
          RecursUntil_d = Convert.ToDateTime(tasks_dr.Field<String>("RecursUntil"));
    }
     else
     {
          RecursUntil_d = DateTime.Now;
     }
     Pattern.RecursUntil = RecursUntil_d;

 appointment.RecurrenceRule = new RecurrenceRule(Pattern);

The Datasourc is an DB which is filled by Datas from an new created Appointment with all values.

Table:

cid      name               type        Value
------- ----------------- ---------- ---
0        id                 INTEGER     n
4        Subject            TEXT       Test
5        Body               TEXT        Test
6        Betreuer           TEXT       69001
7        Startdatum         TEXT      19.04.2012 08:00:00
8        Enddatum           TEXT      19.04.2012 15:00:00
9        Kategorie          TEXT        Fertig
10       Importance         TEXT      Low
11       Ganztag            INTEGER  0
12       Frequency          TEXT      Weekly
13       DayofMonth         INTEGER   0 
14       DayOridnal         INTEGER     0
15       MaxOccurrences     INTEGER  0
16       DaysofWeekMask     TEXT Thursday
17       RecursUntil        TEXT        28.04.2012 15:00:00
18       MonthofYear        INTEGER 0
19       TimeMarker         TEXT        Normal
20       FirstDayOfWeek     INTEGER 1
21       Interval           INTEGER  1

But i get an Error in the Schedule.xaml on InitializeComponent - ArgumentOutOfRangeException
The added or subtracted value results in an unrepresentable DateTime.
Parameter name: value
 
I can't find out wehre the problem is?! Please i need help. Or how to create a Appointment with duration bei Code????

thanks
regards
rene