cookie blocked - poll in iframe on other domain

We have a website placed on a file-system.

In the startpage there is an iframe which load the poll. The poll is placed
on a webserver with only a ip-adres.
So far so good.

Problem
After voting the webbrowser IE6 en IE7 blocks the cookie.

Only after adding the ip of the webserver as a trusted site zone the cookie
will be set.

Is there a possibility to change something so the browser don't block the
cookie without all users adding the ip of the webserver as a trusted site zone?

Please help.

Cookies are not needed since the IP is logged to prevent revoting.

Cookies are not needed since the IP is logged to prevent revoting.

Ip logging is not what we want. In our company there more than one users working on the same workstation. When i activate ip logging only one person per workstation can vote. That's not what we want.

I'd say then that IE's default setting is now set to block cookies that are not coming from the site you are viewing or possibly just doesn't like cookies from I addresses.