oooh that's a toughy. It's kind of hard to give suggestions without looking at your rig. If I were to take a guess, I'd say the action is too low on you E. If you had an ujustable bridge you could fix that in a jiffy.
Honestly, most people on this board are probably going to suggest going to a luthier. However, if you're like me, there isn't one even remotely close. Make sure your bridge feet are flush against the bass and it is perpendicular to the bass (i.e. not slanted). It should be centered whereas the bridge feet are in line with the center notches on the f-holes. Eye usually just eyeball it but there may be a more exact method of attaining this feat. Hope that helps...
