Such problems can happen when your theme or one of your plugins load an old version of jQuery instead of using the version that comes bundled with WordPress.
It can create multiple conflicts with WordPress and with other plugins like Jetpack. You can read more about it here:
http://wordpress.org/support/topic/troubleshooting-wordpress-35-master-list?replies=4#post-3547424
Try switching to a different theme for a few minutes, and check if that solves the issue; if it does, you’ll want to look for the function loading jQuery in your theme’s header.php file, or in the functions.php file. Once you find that function, you can remove it and enqueue the proper version of jQuery as explained here:
http://codex.wordpress.org/Function_Reference/wp_enqueue_script
If the issue is not related to your theme, please try to disable all your plugins, one at a time, until you find the one that causes the conflict. You can then enqueue jQuery using the method I linked to above.
If you do not feel comfortable editing PHP files, you can also contact the theme or plugin author and ask them to solve the issue.
Let me know if this helps.
