I strongly encourage you to find an alternative way to do what you are attempting.
From http://support.microsoft.com/kb/257757
Microsoft does not currently recommend, and does not support, Automation of Microsoft Office applications from any unattended, non-interactive client application or component (including ASP, ASP.NET, DCOM, and NT Services), because Office may exhibit unstable behavior and/or deadlock when Office is run in this environment.
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato