This could be a result of a previous sound card installed on your system. 
Some newer sound cards provide a "fake" A3D.DLL file in order to emulate A3D. 
The problem is that their uninstall programs do not remove this file and leave
it on your hard drive. When your Montego II installation program copies over 
files, it sees that there is already an A3D.DLL file on the system and if it 
sees a newer date, it does not update it.

To solve this problem, simply copy the A3D.DLL from your Montego II CD 
(root directory) over to your Windows System folder, overwriting the one 
currently there.