Playlists Multiplying In Master Audio

Hi, 
I am using dynamic sound group creator to handle playlists in multiple scenes, problem comes when m going back to a previous scene, the local playlists doesn't delete themselves from Master Audio Prefab.
I checked the auto-remove items on dynamic sound creator but i get this error while loading a new scene : 

NullReferenceException: Object reference not set to an instance of an object
PlaylistController.get_PlaylistName () (at Assets/DarkTonic/MasterAudio/Scripts/Utility/PlaylistController.cs:1182)
MasterAudio.DeletePlaylist (System.String playlistName) (at Assets/DarkTonic/MasterAudio/Scripts/Singleton/MasterAudio.cs:3960)
DynamicSoundGroupCreator.RemoveItems () (at Assets/DarkTonic/MasterAudio/Scripts/Utility/DynamicSoundGroupCreator.cs:109)
DynamicSoundGroupCreator.OnDisable () (at Assets/DarkTonic/MasterAudio/Scripts/Utility/DynamicSoundGroupCreator.cs:70)

Using Unity 4.5.1

Please reply ASAP.