I am sorry to have to say that this plugin doesn't work.
It installs OK and appears to configure the single login function ok and gives access to the Admin function from within WordPRess Dashboard however, when I tried to do anything in Admin, it threw me out.
When I logged back in it took me back to the admin page I had just come from, this happened several times, so I looked at the support Forums to see if the issue had been addressed before, and found that others had similar problems.
However, I'd say Zingiri needs to work on their support, as well as the plugin itself, to formulate better responses to support questions. I found those on the boards sketchy and unhelpful, especially given that several users appeared to have the same issues and so clearly these are inherent to the plugin.
I am afraid I must look for another Forum function.
Shame, because I already run a MyBB Forum elsewhere and know its admin pretty well, it's intuitive and well supported, and the CMS BB I installed and customised works well, even with the latest version, so I hoped its integration would be seamless enough.
I am afraid I simply haven't the time to puzzle this out.
When Zingiri Forum is fully functional I may switch to that, if I am not satisfied with whatever else I find in the meanwhile.
Good luck guys!