Exception from HRESULT: 0x80029C4A (TYPE_E_CANTLOADLIBRARY)

I'm creating a windows service on a windows 2003 machine, using dsofile to modify custom properties on a bunch of documents. This works fine until I install the service on a win2k8 machine where it gives me the following error:

ERROR [2010-09-06 13:17:12,317] An unknown error occured: System.InvalidCastException: Unable to cast COM object of type 'DSOFile.OleDocumentPropertiesClass' to interface type 'DSOFile._OleDocumentProperties'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{58968145-CF01-4341-995F-2EE093F6ABA3}' failed due to the following error: Error loading t开发者_C百科ype library/DLL. (Exception from HRESULT: 0x80029C4A (TYPE_E_CANTLOADLIBRARY)).

All my projects are set to run as x86, and Ive used procmon to monitor the files requested without any clues.. Anyone have any ideas on how to solve this?

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Since you have mentioned that you are running a service under Win2008,

• The first clue is, is the DSO File dll component part of Office, what version? is that installed?
• I am not sure if a service can access such a office component running as a system account user which could be open to malicious exploits whilst running under said account as a service...
• TYPE_E_CANTLOADLIBRARY should be as a result of the first option given...

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I had a similar problem and I solved it due to the explanation by Geoff Darst - MSFT. I adjusted his original answer to fit your interface IID:

Sounds like you have a problem with your typelib registration. Presumably, the Com interop layer is hitting the registry to try to locate the typelib. It would start by looking under HKCR\Interface{58968145-CF01-4341-995F-2EE093F6ABA3}\Typelib. The default value should refer to the guid for the typelib that defines the interface in question: which should be located under the following key: HKCR\Typelib{what found in the aforementioned Interface key}. There should be a version subkey and then a 0 subkey, and a win32 subkey under that. The default value of the win32 key should point to the right typelib.