I'm not sure what's going on with your recent Web Poll but it seems like it is possible to vote several times on it??
Typically the poll will allow voting options again after a bit of time browsing the forums.
I doubt that anyone is actually able to vote multiple times though as I am sure you log IP's for each vote.
I am using Firfox Mozilla (1.5.0.2) browser to browse the web site. It merely seems to be a visual bug with the poll I'm thinking.