"You do not have sufficient permissions to access this page."

Hi,
I'm getting this error message when trying to set up A+.

I went once to Settings, didn't change a thing. Tried to go back toit, and I get this message.

I'm logged in a network admin. Obviously, the plugin is running on a site part of a multisite network.

WP 3.6, all plug ins up to date.

Dan