after starting this thread: https://answers.arnoldrenderer.com/questions/13418/cant-render-aovs-in-exr-format-on-win81.html?chil... without a solution,some projects later and many tests in different setups, I found that, aovs written in exr cannot be red properly in older software such as(Ps CC 2015, Nuke 6.3v4) unless, the pass name has equal or less symbols/letters than four.
So passes like coat/sss/Z etc can be red. I understand from the previous responses that it's not profoundly clear to all of you. So I'm asking if there something to be done...or please write it in documentation that Arnold 5 aovs it's not backwards compatible with older exr libraries...