Is your system polls appear on widgets (side bars) only? How to put at Forum topic?
"New poll" button is supposed to appear next to "New topic" button on forums. Make sure you are allowed to create polls (CP->Users » User groups » Set permissions for all groups->Forum)
Secondly, I didn't see "Share" button under the poll itself.
I can not help you with this. The code that you have provided is correct and it works (we have checked) Make sure that you add the code in HTML mode.