When installing ndOffice (or any other Word add-in) you may encounter this error message:
Unable to cast COM object of type 'Microsoft.Office.Interop.Word.DocumentClass' to interface type 'Microsoft.Office.Interop.Word._Document'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{0002096B-0000-0000-C000-000000000046}' failed due to the following error: Error loading type library/DLL. (Exception from HRESULT: 0x80029C4A (TYPE_E_CANTLOADLIBRARY)).
This error stems from a problem with the Office installation. Here’s a link to a Microsoft forum where a similar MS add-in for a product called ACT experiences this and the solution employed to fix it:
http://answers.microsoft.com/en-us/office/forum
See the following article for additional information: