Error after upgrading to Drupal 7

After upgrading to Drupal 7, I'm getting the following error:

The specified file temporary://fileM5GTNG could not be copied, because the destination directory is not pr开发者_高级运维operly configured Drupal 7

I'm sure that the temporary directory is writable by the web server. Also, I notice that javascript files are not being included on my web pages.

The /sites/all/files folder and its children also need to be writeable by the web server, check the permissions on those.

If you've got any performance options switched on it's possible you're not getting the JS files because the system tried to generate static versions in the files folder and failed.