If this is the case, you should remove the extra script(s) reference. If you have a WordPress site, you should be using the wp_enqueue_script() method provided by WordPress. This will ensure that only 1 jQuery script is loaded, and this can now also be used as a dependency for other scripts that are enqueued.
For more information on how wp_enqueue_script() works, check out the WordPress Codex.
Jamie created a video detailing this issue a while back. If you are not sure what to do, watch this: