A few months ago I documented a bug in the Exchange MAPI download that prevents you from loading ExMAPI32.dll directly. The only way to load it was through the MAPI Stub library. This problem is now fixed with the 6.5.8069 update. A few notes:
You must uninstall the Exchange MAPI download before installing the update. If you don’t do this, the update will appear to function, but the DLLs won’t be updated.
The 6.5.8069 update also includes the security fix noted here and here.
The 6.5.8069 update includes the timezone update noted here.