Cant make FBA user site collection admin

I just installed SharePoint 2013 for the company I work for. I installed the FBA Pack and then disabled the Windows Authentication. Then while still logged in with the windows account I could access the new FBA settings and added myself as a user. I closed all browser windows and reopened the main site to log in with the new account. I was able to log in but when I went to the Site Settings, the FBA Settings were gone. Now I can only log in with the one user. I can turn windows auth back on from central admin so users can log in, but that defeats the purpose. I tried requesting access but no matter what group I associated the user with, I still couldn't see the settings.

I'm guessing I need to make the new user a site collection admin but every time I try to add it i get the error "No exact match was found. Click the item(s) that did not resolve for more options." Oddly, it doesn't accept the domain accounts either, I have to click cancel. Maybe there are some powershell commands that can accomplish this?

UPDATE: I modified the machine.config file according to this guide http://blogs.visigo.com/chriscoulson/configuring-forms-based-authentication-in-sharepoint-2013-part-3-editing-the-web-config-files/ and the People Picker recognized the FBA username. I changed the owner to my new account successfully, but it killed the sharepoint app. I deleted the edited machine.config and restored the copy I made and sharepoint works again. My account can now see the FBA settings but the people picker doesn't work on central admin.
I'm guessing you're trying to add the user as a site admin through central admin? If that's the case, in order to see the users you need the membership provider setup in the central admin web.config (or in your machine.config), so that it can be accessed from the central admin site.

Otherwise you can temporarily re-enable windows authentication, and add the users as site collection administrators directly on the site.