I had a similar problem with another plugin (Popup Builder) today, where I could not add images in the editor or switch editor modes as long as YOP Poll was activated.
As far as I could see it was a conflict with the Javascript files.
My (temporary) quickfix was to restrict enqueueing of the scripts in the backend to the YOP Poll page in the backend by using
if($_GET["page"] == "yop-polls") {
[...]
}
around the line
add_action( 'admin_enqueue_scripts', array( &$this, 'load_dependencies' ) );
in the file /admin/admin.php.
Maybe something like this could help?