I'm using uploadify to upload a File to my backend Spring Controller. This controller however checks the user in the current session. This doesn't work in firefox. However when i added the upload.htm;jsessionid=<%=request.getSession().getId()%> to the script it still didn't work. All the time the session was empty. I decided to open up the .fla file and do a popup with the data that got passed in. When I compiled it with CS3 and deployed it, suddenly the upload took the session id into account and everything worked. Could it be that the latest download contains an older swf ?