C# – Accessing Office Word object model through asp.net results in “failed due to the following error: 80070005 Access is denied.”

I have developed a website that allows users to upload office documents then uses the office object model to convert the document to an HTML file that it then displays in an iFrame.

I have, of course, included references to Office.interop.word, and the site works fine on my development machine. When I uploaded it to my production server the site functions fine until I try to upload a document. I initially got a similar error that said "COM object not registered". I realized that Word wasn't installed on my production server. So I installed word and now when the server tries to access the word object model I receive the following error:

Retrieving the COM class factory for component with CLSID {000209FF-0000-0000-C000-000000000046} failed due to the following error: 80070005 Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))

I searched the registry for the corresponding CLSID and found a corresponding folder. I added full control to the IUSR_ account and due to the persistence of the error I eventually added full control to "everyone" and ensured these permissions inherited down to the rest of the folder. I then added full control to IUSR_ and again eventually added full control to "everyone" to my microsoft office folder.

I don't know what other permissions to grant and where in order to make this "Access is denied" error go away. I must be granting them in the wrong place, because as far as I know I can't be any more permissive than "Everyone" "Full Control".

Can anyone shed any light?