Fatal error: Call to undefined function wp() in /home/content/33/7211533/html/someSite/wp-blog-header.php on line 14

can anyone figure whats the problem?

I already update the wp-includes and wp-admin folder, my functions.php is fine

but havent figure how to fix it

any good suggestions?

thanks

----EDIT----

hi guys Im back, theres only 2 plugin installed its the http://wordpress.org/extend/plugins/wp-db-backup/

I cant really figure out on what happen on the website, but what I did to fix this weird problem ,...is I reinstall wordpress , (upload the new copy of wordpress on the site, and I make sure its latest one) - equivalent to a manual update.

After that its started to work fine... so this problem is now fixed...