Retrieving the COM class factory for component with CLSID {00024500-0000-0000-C000-000000000046} failed due to the following error: 80070005

Retrieving the COM class factory for component with CLSID {00024500-0000-0000-C000-000000000046} failed due to the following error: 80070005

seeing exceptions like this make me moan in desperation... spent several hours searching the web...and although i found few good articles on this error here and here, I didn't exactly followed them because in our web app we have impersonating user, so when i opened Component Services->Computers->My Computer->DCOM Config and opened properties on Microsoft Excel Application and would give Launch permissions to this impersonated user.
It didn't work the first time, not the second, so I added this user to the local admins group.
This didn't work much either.
So in the end in some post a line containing 'Event Log' caught my attention and I swiftly opened the event viewer where, under System, found several relevant error messages, one of which

The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID...
gave me the info I needed - turns out I really had to put the ASPNET user account under which asp.net is running.

This solved the problem

I still have doubts as to why the ASPNET account should be held responsible and not the impersonated one, but....whatever!