maicol07 It's OK, I already reversed / uninstalled everything and I have to leave the computer now... I've been on here too long.
Maybe I'll try it again one day. But, just so you know, the problem I experienced was I would log into my WordPress, then go to the forum and I wasn't logged in. I would click login at the forum and the page would just refresh with no changes. It wasn't detecting that I had logged in. I could of course go back to the WordPress site and was logged in. I followed the instructions... put the key in the database, set the user id to me (the admin), installed the plugin and updated the config with the key and my URLs. The URLs seemed to work OK... they redirected to the right places. It just wasn't picking up that I was logged in.
I know this doesn't help though because it could have been many different things.
Has anyone successfully used this with Flarum installed in a folder, not an actual subdomain?