I am currently coding a VB 6 DLL and a VB 6 EXE, each uses Excel 2003.

Both projects require the use of the Office 11 object library, which results
in a reference to the mso.d11 for Office 11, version 11.0.8221.0.

However, certain constants are not defined unless I include the MSO.dll for
what is called the Office 12 object library, version 12.0.6320.5000.

The file is Program Files\Common Files\Microsoft Shared\OFFICE12\mso.dll.
Office 2007 has never been on the computer being used.

Where did that file come from?
From an update to Office 2003?

Neither version is listed at http://support.microsoft.com/dllhelp/.