Meurphy,
Given that you are prone to nightmares I recommend that you avoid using any any paraliminals or training tapes or even photoreading prior to going to bed. Use these tapes in the morning, you mind can process them during the day. Keep the evening free from mind training activities. That also means avoiding meditation in the evenings.
Before anyone complains about my comment on meditation I'll ask them to read this link http://www.sfweekly.com/issues/2002-08-28/bayview.html/1/index.html
I explain in more detail via email.
Alex
