I think you need the directx dll file that you do not get with Windows 7 (I think it is from directx9). There used to be a note about this error in the description page. I belive you need to get this from the directx downloads from microsoft or copy from an XP install. This is all I remember. Sorry.
EDIT: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=2da43d38-db71-4c1b-bc6a-9b6652cd92a3&displaylang=en
Running this should get you the dll file you need.