Thanks otto.
1.upload jquery-ui-1.9.2.custom.min.js to folder “wp-content\themes\arjuna-x\lib”
2.edit “wp-content/themes/arjuna-x/functions.php”:replace “jquery-ui-1.8.10.custom.min.js” with “jquery-ui-1.9.2.custom.min.js”
also runs as smooth as before.