I have the same problem/question as described in this post https://premium.wpmudev.org/forums/topic/users-cannot-access-to-ad-sharing-panel, and no solution.
I've installed the latest version of the Ad Sharing plugin in a network-enabled WordPress installation (latest WP version, with subdomains enabled), activated it network-wide, and saved the settings on the Network Admin configuration page. Still, none of my registered users (any role) can access their panel to paste their own ad codes -- just blog owners/admins.
Now, just to test things out, I installed a single-site WP (latest version) and activated the Ad Sharing plugin -- and things work fine! Users are able to see their ad panels and add their code.
So, essentially, the plugin allows all authors to add their own code on single-site installs, but not on a network-enabled one just the admins. Is that how the plugin is supposed to work? Or is it a bug?
Any help on this would be much appreciated.