It's not a complete fix and more like temp walk around, but it makes this plugin work on other sites in your multi-site installation.
You need to replace function create_poll_table() in wp-polls.php with a new code. That new code will create the tables and options for all blogs/sites. If you added another site after activation of the plugin, you need to deactivate and activate again.
I cannot place that code here - needs a code snippet. If anybody can tell where i can put that code for common access, i'll do that.