NITO TV will not play DVD Decryptor vob files

If I copy using DVDFAB Nito will (after a false start when it reboots) play my films. However no amount of coaxing will get NITO to play the same film copied using DVD DEcrypter. Unfortunately DVDFAB7 takes twice as long to rip as Decryptor, any idea what might be causing this ?

Thanks

Are you using DVD Decrypter to create an ISO or VIDEO_TS folder?

I use it to create Vob files.

Sorry should have said video TS folders in which the vob files sit