Ah, there be the culprit. I know a plethora of guys that have had to go on blood pressure medication and suffer from erectile dysfunction because of it. You could try things like nitric oxide (bodybuilders and weight lifters have used it for years, it's a hemodialator) or horny goat weed, but the sure fire bandage I know of is Viagra or Cialis until you get the blood pressure under control.

Hope that helps ... and beware the 4 hour erection ...