ClassFactory cannot supply requested class

[James J]

I built a .Net Word 2003 application to generate custom reports. It used to
work before I installed Office SP2. My solution contains several projects.
Two of them are Word document report generators. One of them is a Windows
application that provides a user interface that permits users to select the
type of report and the date. Then they click a button to generate the
report. The button click calls a method that creates a reference to a Word
project with:

Imports System.Windows.Forms
Imports Office = Microsoft.Office.Core
Imports Word = Microsoft.Office.Interop.Word
Imports System.IO
Imports System.Net
Imports System.Web
Dim wdDetails As New Microsoft.Office.Interop.Word.Document

I use the wdDetails object to create the Word document in:

projRnPCWordRept._Startup(wapp, wdSummary)
projRnPCWordRept.ThisDocument_Open()

Now I am getting a "ClassFactory cannot supply the requested class" error
when I try to create the document object.

Am I encountering an error because I don't have sufficient privileges? Or
is there something else I should check? Is it no longer possible to do what
I am trying to do?

Thanks,

James J.