Fatal error undefined function is_network_admin()

I am new to Word Press. Like other posters here, I have encountered problems with accessing my administrator page after trying to update automatically from 3.0.4 to version 3.1.1. I re-downloaded WP 3.1.1. into a new folder on my C drive. Following the directions in the Read Me file, I opened my wp-config-sample.php file and entered my database information and saved the file as wp-config.php. Now I am stumped as to how to upload this config file onto my ftp site. I am familiar with uploading onto ftp sites, but when I go into my ftp account via Mozilla, I am unsure as to which folder in the index directory I should upload the config file. I would appreciate any help you can give me. Thanks.