Issues with Word 2002 and Acrobat 9

We installed Acrobat Pro version 9 a couple of weeks ago, and began experiencing problems with a couple of our VB.NET apps that invoke Word 2002. Basically, it appears that the presence of Acrobat Pro 9 causes Word 2002 to stop interacting with some VB commands.T

These same VB.NET apps function without incident under Acrobat Pro version 8.

We are running Acrobat Pro version 9.1.3 and Word XP(2002). The VB.NET apps were developed using Visual Studio 2005 version 8 and .NET Framework version 2. We are using Windows XP Professional SP3.

The specific error message being generated by the .NET apps is:

Unable to cast COM object of type 'Word.ApplicationClass' to interface type 'Word._Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00020970-0000-0000-C000-000000000046}' failed due to the following error: Library not registered. (Exception from HRESULT: 0x8002801D (TYPE_E_LIBNOTREGISTERED)).

The error is thrown when the app attempts to open a Word document.

Has anyone encountered this problem? Do you know of any web sites I could check that could possibly help out? I've already searched the MS knowledgebase to no avail. I'd appreciate any assistance.

Thanks!