The permissions are set in the core files, so the best way to do this would be with a very simple plugin that overrides the core permissions.
Here's a gist that shows how to deny permissions to contributor.
The permissions are set in the core files, so the best way to do this would be with a very simple plugin that overrides the core permissions.
Here's a gist that shows how to deny permissions to contributor.
It could be a permissions problem, that the server can't read the directory or files.
All you really need is the directories like this:
plugins/ContributePerm/plugin.php