500 Error When Creating Pages From Custom Master Page

Hi all,

Just installed a new instal of Runway and am trying to create some new pages from a custom master page, but none of the regions are displaying in Perch admin plus if I click on View Page I get a 500 error.

Server's error log shows...

2018-11-19 13:33:54.083703 [INFO] [80.229.221.55:52941-Q:5601380942510994594-43] File not found [/home/annamace/public_html/404.shtml] 
2018-11-19 13:33:54.083636 [INFO] [80.229.221.55:52941-Q:5601380942510994594-43] File not found [/home/annamace/public_html/cms/core/apps/content/page/url/free-sample/] 

If I create a page using the default master page that comes with Runway it works fine.

Custom master page looks like this...

<?php
    perch_layout('global/head', [
        'css' => '<link rel="stylesheet" href="/assets/tropic_skincare/css/free_sample.css">'
    ]);

    perch_content('H1 Title');

    perch_layout('global/js');
    perch_layout('tropic_skincare/tracking');

    PerchUtil::output_debug();

Any ideas?

Diagnostics...

Perch Runway: 3.1.3, PHP: 7.0.32, MySQL: 10.1.36-MariaDB, with PDO
Server OS: Linux, litespeed
Installed apps: content (3.1.3), assets (3.1.3), categories (3.1.3), perch_forms (1.12), perch_mailchimp (3.1)
App runtimes: <?php $apps_list = [ 'perch_forms', 'perch_mailchimp' ];
PERCH_LOGINPATH: /cms
PERCH_PATH: /home/annamace/public_html/cms
PERCH_CORE: /home/annamace/public_html/cms/core
PERCH_RESFILEPATH: /home/annamace/public_html/cms/resources
Image manipulation: GD Imagick
PHP limits: Max upload 50M, Max POST 50M, Memory: 128M, Total max file upload: 50M
F1: 3b606135b33e6a102526838f4152a807
Resource folder writeable: Yes
HTTP_HOST: annamace.co.uk
DOCUMENT_ROOT: /home/annamace/public_html
REQUEST_URI: /cms/core/settings/diagnostics/
SCRIPT_NAME: /cms/core/settings/diagnostics/index.php