[@chrishajer Participant 18 years ago]

Did you add that to wp-config.php as the first line, right after the <?php?

The error cannot redeclare means something has already been included that it’s trying to include again.

http://www.google.com/search?q=Cannot+redeclare+_http_build_query()

https://bbpress.org/forums/topic/having-trouble-integrating-wp-functions