The output of Chrome error console says:

Uncaught TypeError: Cannot read property 'fid' of undefined		/sites/all/modules/swfupload/js/swfupload_widget.js?x:715
SWFU.ref.uploadSuccess		                                    /sites/all/modules/swfupload/js/swfupload_widget.js?x:715
(anonymous function)                                          /sites/all/libraries/swfupload/swfupload.js?x:725
SWFUpload.executeNextEvent                                    /sites/all/libraries/swfupload/swfupload.js?x:745
(anonymous function)                                          /sites/all/libraries/swfupload/swfupload.js?x:730


And Mozilla Firebug console gives:

server_data.file is undefined
uploadSuccess(file=Object { more...}, server_data=Object { ... })               swfupload-widget.js?x (line 715)
(?)()                                                                           swfupload.js?x (line 725)
executeNextEvent()	                                                            swfupload.js?x (line 745)
(?)()                                                                           swfupload.js?x (line 730)