My WordPress install has occasional bursts when it can’t auto-upgrade plugins or itself. There has been an issue with image upload through ScribeFire as well. I’ve tried various things that haven’t worked. This is the first time that I’ve seen the different directory and file permissions argument, so gave it a go, and it does appear to be working. I haven’t had a WordPress or plugin upgrade since I did it, though, so still a work in progress. As well as the permissions, I chowned the files to be owned by my user account and grouped as nobody, so hopefully the server-created files are changeable as well.