Import the following Management Packs from the ManagementPacks folder located on the DPM installation DVD or installation ...

Import the following Management Packs from the ManagementPacks folder located on the DPM installation DVD or installation file location: 
   - Microsoft.SystemCenter.DataProtectionManager.2012.Library.mp
   - Microsoft.SystemCenter.DataProtectionManager.2012.Discovery.mp. 
and then run the prerequisites check again.