So what do I do now?
You must restore your config.php.
Find the old config.php in my backup or?
I hope. If you have used the standard WB backup tool, you will have no backup from config.php. If you have used another backup-tool, you will only have a backup if you have also made backup of your files. The config.php should look like this:
Only registered users can see contents. Please click here to Register or Login.
Replace the "x" with the datas from your hoster.
Where to find the changed-file package?
You find all in the first post.
So what should you do now:
1.) Replace the config.php with the one from your backup or create a newone from the example
2.) Download the "changed_file" Package from the first post, unzip it and upload all files to your webspace
3.) Run the upgrade-script again.