COMException when connecting events

I get a COMException when trying to connect an event...

I've added a reference to the MessengerAPI interface (windows messenger) to my project.

Code:

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private MessengerClass _Messenger = new MessengerClass();

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// class definition in the messengerapi
properties and methods are all working fine but when I try to connect an event (any event from this reference) it throws a COMException:

Code:

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_Messenger.OnContactBlockChange += new DMessengerEvents_OnContactBlockChangeEventHandler(this.DoContactBlockChange);

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System.Runtime.InteropServices.COMException (0x80040202): Exception from HRESULT: 0x80040202.
at System.Runtime.InteropServices.UCOMIConnectionPoint.Advise(Object pUnkSink, Int32& pdwCookie)
at MessengerAPI.DMessengerEvents_EventProvider.add_OnContactBlockChange(DMessengerEvents_OnContactBlock ChangeEventHandler )
at MessengerAPI.MessengerClass.add_OnContactBlockChange(DMessengerEvents_OnContactBlockChangeEventHandl er )


I tried it also in a VB.NET project which connects the events automaticaly and it also throws the same COMException... anybody any idea what the problem is here?
thnx, Charly