thanks for your comments. Here is what I found confusing:
I installed Poll first as described above. In addition to Poll being installed it automatically picked some other requirements. z3cform I think was one. they showed up in the “Add”. I added poll and these new products.
When i tried to use Poll, I got the issue as described above.
So i created a clean installation of Plone 5.0.8, installed Poll 1.10. Installed smoothly, but without the other products. Don’t know why.
I tried Poll on this new installation, and it worked fine.
I don’t know if this is of any interest; however, I thought I close the loop and let others know.