Fatal error css-related

Assistance, please:

I’m getting this in the upgrade process:

Fatal error: Call to undefined function: wp_admin_css() in /home/content/G/o/g/xxxxx/html/wordpress-1/wp-admin/upgrade.php on line 21

before that I got:

Warning: main(/home/content/G/o/g/Gogators0/html/wordpress-1/wp-settings.php): failed to open stream: No such file or directory in /home/content/G/o/g/xxx/html/wordpress-1/wp-config.php on line 22

I added the settings from the backup and it moved on to the problem at the top

xxx = deleted by me

thanks in advance