Upgrade help!

Hello,
I just updated wordpress to the newest version. Everything went fine until the fact when I went to the site, I’m getting the following error:

Warning: main(./wp-blog-header.php) [function.main]: failed to open stream: No such file or directory in /home/*****//public_html/saanamsmind.com/index.php on line 17

Warning: main(./wp-blog-header.php) [function.main]: failed to open stream: No such file or directory in /home/*****//public_html/saanamsmind.com/index.php on line 17

Fatal error: main() [function.require]: Failed opening required './wp-blog-header.php' (include_path='/usr/lib/php:.:/usr/php4/lib/php:/usr/local/php4/lib/php') in /home/*****/public_html/saanamsmind.com/index.php on line 17

I can’t figure out what I’ve done wrong. I followed all the instructions step by step for the upgrade.

Please help!