If you want to use the latest features and fixes of Shoppica you have to upgrade to opencart 1.5.x and then apply the latest version of Shoppica. Be aware that the OC upgrade from 1.4 to 1.5 is not very easy for the average user. Basically most of the people just make a clean install with the latest opencart version and add their products manually.
Again – check wich version of OpenCart you are currently using. If it is 1.4.9.x, you have to upgrade opencart with the default theme first and then install the newest Shoppica.