Fatal error : Call to undefined function wp_redirect

Hi, I’m new to wordpress.. I’ve upgraped wordpress to version 2.9, and I failure to add/edit new post, the Fatal error: Call to undefined function wp_redirect() in /home/secret/public_html/wp-admin/admin.php on line 33.

The line 33 show in admin.php is :
wp_redirect(admin_url(‘upgrade.php?_wp_http_referer=’ . urlencode(stripslashes($_SERVER[‘REQUEST_URI’]))));

Can you please help to solve the problem?
Thanks.