Application.Filesearch generates Error 430 'Class does not support

[JDB]

Hello,

We are running Office 2003. A third-party application calls a Word macro to
do a mail merge, and the following error occurs:

Error 430 'Class does not support automation or does not support expected
interface'

Here is a portion of the code, the VBA debugger identifies the With
Application.Filesearch line to be the problem:

If lastMergeDocumentIx = 0 Or mergeFileNameList(currentMergeDocumentIx) <>
mergeFileName Then
With Application.FileSearch
.LookIn = Options.DefaultFilePath(wdDocumentsPath)
.FileName = mergeOnlyName
If .Execute > 0 Then
Documents.Open mergeFileName
lastMergeDocumentIx = lastMergeDocumentIx + 1
' Don't continue if we've exceeded the bounds of the table.
If lastMergeDocumentIx <= TableMax Then
currentMergeDocumentIx = lastMergeDocumentIx
mergeFileNameList(currentMergeDocumentIx) = mergeFileName
Set mergeDocumentList(currentMergeDocumentIx) =
ActiveDocument
End If
End If
End With
End If

This works fine on some computers, but others get the 430 error. I've tried
all the following resolutions, but none have worked:

1. Reinstalled MDAC
2. Upgraded MDAC
3. Installed the MDAC version that is installed on the working computers
4. Installed JET 4 SP8
5. Reregistered the Word 2003 type library

Any help would be greatly appreciated!
Thanks,
Jeff