As to the link to the poll...... HUH? LOL! I thought all I had to do was click on start new poll, and fill in the blanks! It worked fine for 3 people so I don't understand why others can't see it. I still have the buttons but then I haven't voted.
OK... You have an existing poll, where your users are having trouble voting, or your users are having troubles starting new polls?
If the first, can you give me a link to the poll they're having problems voting in. If the second, have a look in your "Edit Forums" -> "Edit Settings" screen, on "Who can start new polls".