4ndy,
Since the yearning for results approach has not worked for you, have you tried simply listening to the tapes with no intention what-so-ever?
That is, you might want to try deciding to listen to the tapes at some point just to listen to them ... and not knowing exactly what to expect.
Just make it a habit to listen to one every night or morning or whatever, let yourself shut off consciously and not do anything (have no goals), and just allow yourself to be receptive and respond to the tape in any way that is particularly natural to you.
After a month, you might find that some important things that were outside of your awareness have changed.
Sometimes in our attempts to make things work for us, we prevent them from helping. That is, the activity of our conscious minds can interfere with the development of unconscious learnings.