Sessions and uploadify
you cannot solve this because uploadify has own session ID which is created by flash player. In other words the flash player access the uploadify script as a new user and gets a new session. The only way you can solve this is to pass current page session_id through post to the uploadify script.
I found a solution which is far easier to implement, especially if you already have a session-oriented PHP backend for login, etc.:
just write the following code in the jQuery statement:
'script' : '/upload.php?<?= session_name(); ?>=<?= session_id(); ?>',which will magically attach your current session name and your session id.