Can't see the top menu with all the options for IMCE

TypeError: menu.parent(...).offset(...) is null
http://ithinkdesi.com/new/sites/all/themes/tb_magz/js/tb_magz.js?n9xc9i
Line 110

I used Firebug to find out why the top menu with all the options won't work.
It was a bug in the Javascript as shown above.
May I know how to fix it.
PS: I am new to Drupal, so no coding or hard stuff please.