Enabling module disallows access to all pages

When I enable this module, access is immediately restricted to all pages to all users, including uid=1. Have I missed something in the set up (create table, enable module)?

I assume the module immediately starts working without any access rules, but I can't get at any site pages, let alone the 'url' tab under access control to administer the access rules.

(On a 4.7.0-beta-6 install with today's HEAD of path_access).

Please tell me its just lack of coffee on my part - this module sounds perfect for our current project, and several others!