Transferred WordPress to Hostgator with fatal error

I migrated the site to Hostgator, which apparently worked successfully until I changed the nameservers to point to Hostgator. Now the site is showing the following error and I have no access to the dashboard or the site.

Fatal error: Uncaught Error: Call to undefined function wp() in /home2/xxx/zulalodge.co.nz/wp-blog-header.php:16 Stack trace: #0 /home2/xxx/zulalodge.co.nz/index.php(17): require() #1 {main} thrown in /home2/xxx/zulalodge.co.nz/wp-blog-header.php on line 16

The page I need help with: [log in to see the link]