Communicator VBA Issue (1 Viewer)

[graviz]

I'm trying to send a message via Office Communicator using vba and am having some issues. I'm getting an the error "Invalid Procedue or Arguement" on the "Set msgr = Messenger.InstantMessage(ToUser)" line.

Option Compare Database
Public Sub sendIM(ToUser As String, message As String)
 
Dim msgr As CommunicatorAPI.IMessengerConversationWndAdvanced
 
Set msgr = Messenger.InstantMessage(ToUser)
 
msgr.SendText (message)
 
End Sub
 
Function runthis()
 
Call sendIM("Taylor, Jon", "test")
 
End Function

Any ideas?