Permissions error when submitting for review

I’m attempting to configure this plugin on my websites, and I get through all of the steps successfully until I get to “Submit for Review”. When I click this, I get an error that simply says “Permissions error”

I’ve checked the PHP error logs and see nothing related to this, and I don’t have any problems with other plugins writing to the file system, so I doubt that’s the cause either.

Any ideas? Is this an issue with configuration of my app at Facebook?