Upgraded now all messed up :(

I went to use the automatic update , backed up all files, then it said it couldnt work.

So I click on the upgrade link in the admin dashboard ( since i had my files backed up from 1st try )….

It finishes and shows this error :
Downloading update from https://www.ads-software.com/wordpress-2.8.zip
Unpacking the core update
Verifying the unpacked files
Installing the latest version
Could not copy file: /public_html/wp-admin/images/visit-site-button-grad.gif
Installation Failed

I click on any button to go back to dashboard and get the following error :
Fatal error: Call to undefined function set_screen_options() in /home/extended/public_html/wp-admin/admin.php on line 45

Can anyone please tell me how to fix this? or how to install my backups?

My site is https://www.extendedviews.com