Fatal error: Call to undefined function get_header()

Try re-uploading the wp-includes folder from a fresh download of WordPress.

Hi esmi, thanks. I figured some of the files in the root had gone corrupt (maybe I accidentally have overwritten some files), so I just reinstalled WP. That worked. I did not loose any data or anything, it’s just a development environment.

I’ve got the same error on englishcollective.org. Not sure if this is related, but I had just added the post_is_in_descendant_category funtion to my theme’s functions.php file. I’ve tried replacing the whole wp-include directory, but that didn’t work. I’m panicking because I don’t know what to do next. Any ideas?

Fixed it. I put the theme’s index.php in the WordPress root accidentally, because of an ftp error on my server. Phew!

hey dude, just simply way to remove that’s messages..
function get_header() in <– on index.php

open up your index.php

u may found <?php get_header();

add @ before get_header();

show this code like this
<?php @get_header();

n u hv got blank..on that directory but your theme work

All you’re suggesting is making the error. It needs to be fixed. get_header usually does far more than load a pretty picture for the top of the pages.