PHP Warnings About Header Information

Hi,

I recently transferred a site from my localhost to my online server, but I'm getting this error message and I cannot seem to pinpoint how to fix it. It says:

"Warning: Cannot modify header information - headers already sent by (output started at /home/gregston/public_html/gospelcenteredworship.com/about.php:6) in /home/gregston/public_html/gospelcenteredworship.com/perch/core/lib/PerchUtil.class.php on line 1211

Warning: Cannot modify header information - headers already sent by (output started at /home/gregston/public_html/gospelcenteredworship.com/about.php:6) in /home/gregston/public_html/gospelcenteredworship.com/perch/core/lib/PerchUtil.class.php on line 1212

Warning: Cannot modify header information - headers already sent by (output started at /home/gregston/public_html/gospelcenteredworship.com/about.php:6) in /home/gregston/public_html/gospelcenteredworship.com/perch/core/lib/PerchUtil.class.php on line 1213

Warning: Cannot modify header information - headers already sent by (output started at /home/gregston/public_html/gospelcenteredworship.com/about.php:6) in /home/gregston/public_html/gospelcenteredworship.com/perch/core/lib/PerchUtil.class.php on line 1219"

Here's an image of it: https://d.pr/i/zhio

And here's my diagnostic report

Perch: 2.8.34
Production mode: Production (100)
Installed apps: content (2.8.34), assets (2.8.34), categories (2.8.34), perch_blog (5.0), perch_forms (1.8.3)
DB driver: PDO
DB tables: perch2_blog_authors (1), perch2_blog_comments (0), perch2_blog_index (23), perch2_blog_posts (1), perch2_blog_posts_to_tags (0), perch2_blog_sections (1), perch2_blog_tags (0), perch2_blogs (1), perch2_categories (0), perch2_category_counts (0), perch2_category_sets (1), perch2_content_index (13), perch2_content_items (4), perch2_content_regions (2), perch2_navigation (0), perch2_navigation_pages (0), perch2_page_templates (0), perch2_pages (1), perch2_resource_log (7), perch2_resource_tags (0), perch2_resources (5), perch2_resources_to_tags (0), perch2_settings (12), perch2_user_passwords (0), perch2_user_privileges (34), perch2_user_role_privileges (16), perch2_user_roles (2), perch2_users (1)
Users: 1
PHPMailer: 5.2.21
App runtimes:
<?php
    $apps_list = array(
        'content', 
        'categories',
        'perch_blog',
        'perch_forms',
    );
Scheduled tasks for perch_blog: delete_spam_comments (1440 mins)
Editor plug-ins: markitup
H1: 233a2250f5937c8d86e633e14c559f2f
L1: 7427f22896e26c68b23f8d84d388dcb5
F1: 6a33f95eca3667f9e0c39bf5ca2980fe
headerColour: #ffffff
content_singlePageEdit: 1
helpURL:
siteURL: /
hideBranding: 0
content_collapseList: 1
lang: en-gb
update_2.8.34: done
latest_version: 2.8.15
on_sale_version: 2.8.34
perch_blog_update: 5.0.1
perch_blog_post_url: /blog/post.php?s={postSlug}
PERCH_DEVELOPMENT: 10
PERCH_STAGING: 50
PERCH_PRODUCTION: 100
PERCH_DB_USERNAME: gregston_champki
PERCH_DB_SERVER: localhost
PERCH_DB_DATABASE: gregston_gcw
PERCH_DB_PREFIX: perch2_
PERCH_TZ: UTC
PERCH_EMAIL_FROM: greg@champkiddesign.com
PERCH_EMAIL_FROM_NAME: Greg Stone
PERCH_LOGINPATH: /perch
PERCH_PATH: /home/gregston/public_html/gospelcenteredworship.com/perch
PERCH_CORE: /home/gregston/public_html/gospelcenteredworship.com/perch/core
PERCH_RESFILEPATH: /home/gregston/public_html/gospelcenteredworship.com/perch/resources
PERCH_RESPATH: /perch/resources
PERCH_HTML5: 1
PERCH_RUNWAY:
PERCH_ERROR_MODE: DIE
PERCH_DATE_LONG: %d %B %Y
PERCH_DATE_SHORT: %d %b %Y
PERCH_TIME_SHORT: %H:%M
PERCH_TIME_LONG: %H:%M:%S
PERCH_RUNWAY_ROUTED:
PERCH_STRONG_PASSWORDS:
PERCH_DEBUG:
PERCH_PREVIEW_ARG: preview
PERCH_TEMPLATE_PATH: /home/gregston/public_html/gospelcenteredworship.com/perch/templates
PERCH_DEFAULT_DOC: index.php
PERCH_DEFAULT_EXT: .php
PERCH_PRODUCTION_MODE: 100
PERCH_RWD:
PERCH_HTML_ENTITIES:
PERCH_SSL:
PERCH_STRIPSLASHES:
PERCH_PROGRESSIVE_FLUSH: 1
PERCH_PARANOID:
PERCH_FORCE_SECURE_COOKIES:
PERCH_PASSWORD_MIN_LENGTH: 6
PERCH_MAX_FAILED_LOGINS: 10
PERCH_AUTH_LOCKOUT_DURATION: 1 HOUR
PERCH_VERIFY_UPLOADS:
PERCH_AUTH_PLUGIN:
PERCH_DB_CHARSET: utf8
PERCH_DB_PORT:
PERCH_DB_SOCKET:
PERCH_SESSION_TIMEOUT_MINS: 20
HOSTING SETTINGS

PHP: 5.6.30
Zend: 2.6.0
OS: Linux
SAPI: cgi-fcgi
Safe mode: not detected
MySQL client: mysqlnd 5.0.11-dev - 20120503 - $Id: 76b08b24596e12d4553bd41fc93cccd5bac2fe7a $
MySQL server: 5.6.35
Free disk space: 828.62 GB
Extensions: Core, date, ereg, libxml, openssl, pcre, zlib, filter, hash, pcntl, readline, Reflection, SPL, session, standard, cgi-fcgi, bcmath, bz2, calendar, ctype, curl, dom, mbstring, fileinfo, ftp, gd, gettext, iconv, imagick, imap, intl, json, magickwand, exif, mcrypt, mysqlnd, mysql, mysqli, PDO, pdo_mysql, pdo_sqlite, Phar, posix, pspell, SimpleXML, soap, sockets, sqlite3, tidy, tokenizer, xml, wddx, xmlreader, xmlrpc, xmlwriter, xsl, zip, mhash, ionCube Loader, Zend Guard Loader, Zend OPcache
GD: Yes
ImageMagick: Yes
PHP max upload size: 64M
PHP max form post size: 64M
PHP memory limit: 128M
Total max uploadable file size: 64M
Resource folder writeable: Yes
Session timeout: 24 minutes
Native JSON: Yes
Filter functions: Yes
Transliteration functions: Yes
CONTEXT_DOCUMENT_ROOT: /home/gregston/public_html/gospelcenteredworship.com
DOCUMENT_ROOT: /home/gregston/public_html/gospelcenteredworship.com
GATEWAY_INTERFACE: CGI/1.1
HTTP_ACCEPT: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
HTTP_ACCEPT_ENCODING: gzip, deflate, sdch
HTTP_ACCEPT_LANGUAGE: en-US,en;q=0.8
HTTP_CONNECTION: keep-alive
HTTP_COOKIE: cmsa=1; PHPSESSID=rlsh4rp3njbj0q156f31q9tq17
HTTP_HOST: gospelcenteredworship.com
HTTP_REFERER: https://gospelcenteredworship.com/perch/core/settings/diagnostics/
HTTP_UPGRADE_INSECURE_REQUESTS: 1
HTTP_USER_AGENT: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36
PATH: /bin:/usr/bin
PHP_INI_SCAN_DIR: /opt/cpanel/ea-php56/root/etc/php.d/:/home/gregston/public_html
QUERY_STRING: extended
REDIRECT_STATUS: 200
REMOTE_ADDR: 72.35.152.249
REMOTE_PORT: 46878
REQUEST_METHOD: GET
REQUEST_SCHEME: http
REQUEST_URI: /perch/core/settings/diagnostics/?extended
SCRIPT_FILENAME: /home/gregston/public_html/gospelcenteredworship.com/perch/core/settings/diagnostics/index.php
SCRIPT_NAME: /perch/core/settings/diagnostics/index.php
SERVER_ADDR: 67.212.235.130
SERVER_ADMIN: webmaster@gospelcenteredworship.gregstonedesign.com
SERVER_NAME: gospelcenteredworship.com
SERVER_PORT: 80
SERVER_PROTOCOL: HTTP/1.1
SERVER_SOFTWARE: Apache
UNIQUE_ID: WKOd9eRSPJw1RI3axtWS8wAAAA8
PHP_SELF: /perch/core/settings/diagnostics/index.php
REQUEST_TIME_FLOAT: 1487117813.34
REQUEST_TIME: 1487117813
argc: 1