Poll script

Can anyone recommend a good poll script? I would like to find one that is freely available, has a password protected control panel and can set up polls protected from multiple voting by at least IP and cookie checks.

Not sure on a precise script.
But check out HotScripts: www.hotscripts.com

Check this one: http://www.limesurvey.org/

Thanks for your recommendations.
On Limesurvey I have installed this script. The index page generated an error:
Warning: require_once(home/xxxxxx/public_html/amaranti/limesurvey/classes/adodb/adodb.inc.php) [function.require-once]: failed to open stream: No such file or directory in /home/xxxxxx/public_html/amaranti/limesurvey/common.php on line 57
I don't really have the knowledge to figure out errors like this and would really like a script which sets up straightforwardly.
On Hotscripts many scripts require a fee and I wouldn't pay any fee for a script I could not check first. Many others are four or so years old and others do not match my fairly simple requirements.
All I am really looking for is a straightforward poll script with a password protected control panel, controls on multiple voting using cookies and IPs and a simple page for setting up new polls.