Image previewer add-on.
Are you able to access the i18n_pane.properties directly in browser ?
I put the .properties files in the same folder of the .xhtml file that calls the .jsp file and tested the application on every single computer at my office and found something interesting:
Windows PCs : ok on firefox and IE
on Ubuntu PCs I got 3 types of response:
some computers did the upload ok
some computers couldn't load the applet but loaded ok the one from the .html file provided with the zip
some computers load applets but couldn't load the jFileUpload applet, not even from the demo page at http://www.jfileupload.com