function issue

I am working with Genesis lifestyle theme, which involves a lot of coding to make changes.
I had my site live and then made a entry in the funtions.php file in the child theme to add a favicon as per the instructions on their website.
Then my screen went white.
I have rebuilt the site and backed up while I was going along. I went to do another entry in the functions file again and the same thing happened.
I then deleted the entire website and restored my back up however, I am getting this message:
Warning: require_once() [function.require-once]: Unable to access /home/engageau/public_html/wp-content/themes/genesis/lib/classes/admin.php in /home/engageau/public_html/wp-content/themes/genesis/lib/init.php on line 169

Warning: require_once(/home/engageau/public_html/wp-content/themes/genesis/lib/classes/admin.php) [function.require-once]: failed to open stream: No such file or directory in /home/engageau/public_html/wp-content/themes/genesis/lib/init.php on line 169

Fatal error: require_once() [function.require]: Failed opening required ‘/home/engageau/public_html/wp-content/themes/genesis/lib/classes/admin.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/engageau/public_html/wp-content/themes/genesis/lib/init.php on line 169.

I have looked in this file from file manager in cpanel but I can’t see anything wrong.
Can you please help before I have to rebuild it a third time.
https://www.engagedbirthdoula.com.au