I've installed WPMU on EC2 with a Bitnami AMI. It all seems to be working but not only can I not upload to Blogs.dir, but apparently I can't change the default Media upload file, or the upload file structure. I got hacked real bad recently and don't want to risk a 777 directory. I've looked at the various workarounds but wondering if I've missed something.
I saw this hack which 'MAY' work.
define('FS_CHMOD_DIR', (0755 & ~ umask()));
define('FS_CHMOD_FILE', (0644 & ~ umask()));
and, (which seems pretty simple, but will it work on WPMU?)