are you using zmapper to get your normal maps? because I remember when i used to use zmapper within zbrush i got these sorts of errors sometimes and you have to edit them in photoshop and smudge over the seams.
what does your low polys UVs look like? if you could give a snapshot that would be cool. if they are like the ones from your normal map above then that could be why you are getting weird results because the texture resolution is unevenly spread across each polygon in your model. a half hour in the UV unwrap editor (sorry havent used max in ages) could sort it and then reimport into zbrush as your low mesh and try again
if im wrong i apologise, good luck anyway bud