Failed to create flowsheet object

[HenkF]

Hi, I run into a problem when using COFe.xlt.
When I create a new flosheet within Excel using the COFE template there is no problem : the flowsheet is created, and property and flow data can be used. When I however like to open an existing flowsheet, it shows me the following message - in Dutch : Title: "Failed to create flowsheet object"; message : "Eigenschap Add van klasse OleObjects kan niet worden opgehaald" (in English something like "Property Add of class OleObjects cannot be created /collected"?). I'm using Excel 2010/Windows 7. Does someone have any clues regarding this issue? Thanks!
regards,
Henk

[HenkF]

...a next messgage screen reads:
Title: "No Flowsheet document"
Message: "COFE Excel documents requiere an excel dcument to be present; the document now will close"
These message are generated while working in Excel.
Henk

[jasper]

[HenkF]

Jasper, thanks for your reply and hints.
I guess it has to do with my setup, as at another system it indeed runs OK. Maybe a lost reference?
I'm going to dig deeper in using your suggestions.

Thanks!
Henk