If you could please update your plugin in the future to accomodate for this, I would appreciate it.
For those that have run into the same issue as I have, here's what I did to fix it. In the file ultimate-tag-cloud-widget.php, I added the following line to the list of other defines:
define("UTCW_DEFAULT_PLUGIN_PATH", plugin_dir_url(__FILE__) );
Scroll down to near the bottom of the file (around Line 960) to find the registration of the JS and CSS files. Change them to:
wp_register_script('utcw-js', UTCW_DEFAULT_PLUGIN_PATH . 'utcw.min.js', array('jquery'), "1.3", false); wp_register_style('utcw-css', UTCW_DEFAULT_PLUGIN_PATH . 'utcw.min.css', array(), "1.3", 'all');
This should fix the issue.