EDIT: Just downloaded the new version and am installing it now. If you look in Control Panel > Programs > Programs and Features (for Vista, XP should be similar), you can see Media Manager listed in your installed programs. The new version is version '2.4', while the old is version '2.3.' The file download has the name mediamanager24 while the older version is named mediamanager23_enu. As I was typing this, the installation finished and it does indeed appear as though MM works just fine.
Check your installed programs for the version listed--old is v2.3, new is v2.4.
EDIT #2: Oops...it *is* version 2.4, not '24'. Sorry for the confusion.
TB