MX SDK - Accessing Model.fil

There appears to be an issue in the MX SDK for V8i SS4

The following code opens MX modelfie, and allows access to the model.fil from VBA
Dim mxFil As MXModelFile
Set mxFil = New MXModelFile
Dim ret As
Boolean
ret = mxFil.OpenMXModel(True)

in SS2 the value of ret is true

For the same code in SS4 the value returned to ret is false (i'e not opened)

I have changed the references to the correct version of MXModelLib.dll (in C:\Program Files (x86)\Common Files\Bentley Shared\MX\08.11.09).
I can get this to work from a Microstation VBA macro. but this code does not wor k from Excel VBA or any appication external to Microstation.

any Ideas?

Thanks

Mark