Can anyone please help on this

Ive found some code to insert a calendar event into outlook, ive seen loads and loads of posts with this same code but none of them work

heres the code

VB Code:
  1. Private o1 As New Outlook.Application

  2.     Public Sub CreateAppointment() 'CreateAppointment(ByVal StartTime As Date, ByVal Endtime As Date, ByVal Subject As String, ByVal Location As String)

  3.         Try

  4.             'Create a reference to a Appointment item

  5.             Dim e1 As Outlook.AppointmentItem

  6.             'Create a new appointment item

  7.             e1 = o1.CreateItem(olAppointmentItem)

  8.             'Set a few of the many possible appointment parameters.

  9.  
  10.             e1.Start = CDate("23/01/2004 09:00:00")

  11.             e1.End = CDate("23/01/2004 10:00:00")

  12.             e1.Subject = "test"

  13.             e1.Location = "Bournemouth"

  14.             'If you want to set a list of recipients, do it like this

  15.             'e1.Recipients.Add Name

  16.             'Commit the appointment

  17.             e1.Send()

  18.             'Free up the space

  19.             e1 = Nothing

  20.         Catch er As Exception

  21.             MsgBox(er.ToString)

  22.         End Try

  23.     End Sub

i keep getting an error of

"System.InvalidCastExeception: Specified cast is not valid"

ive also found this but havnt tried it as of yet

http://support.microsoft.com/default...;en-us;Q309336

Is this article releated to my problem