After resetting the user roles to default the following error shows up when I visit the Usergroups page, logged in as an admin.
Sorry, you do not have permission to edit usergroups.
I was able to edit them before and I'm an administrator. I do have the User Role Editor installed, but that wasn't giving me problems before, plus I can't even edit the administrator user role in that, so it's still the same.
http://wordpress.org/extend/plugins/edit-flow/
Edit Flow uses custom capabilities for usergroup management and post subscriptions (who should be notified of emails).
To manage usergroups: edit_usergroups
To manage subscriptions: edit_post_subscriptions
Just assign those caps to the the necessary roles/users and that should work.
No, I can't. The administrator role is the default administrator role and cannot be changed by the user role editor.
You can use a plugin like Role Scoper or Members instead.
I'll check it out, but I'm using the default roles (administrator, editor, author, etc).