What do errors like these mean:
session_start(): PrivoxyWindowOpen(/tmp/sess_be09512603dfe7ca99751ee0ded7fbad, O_RDWR) failed: Permission denied (11)
Fatal error: session_start(): Failed to initialize storage module: user (path: /tmp)
This means your PHP install isn't configured correctly. PHP can't create the session datafiles. Contact your admin or read the PHP docs to setup session handling correctly.
I was getting this error message as well. It was a PHP configuration problem as described above. I fixed the problem by editing the php.ini file and setting this directive to a directory that existed… it had previously been /tmp by default (expecting to be hosted on a *nix server. So if you are running PHP on Windows you have to change it, just keep the / instead of using the windows \.
session.save_path = c:/temp
Note that on Windows, you have to modify the save handler to files
session.save_handler = files