Cannot send session cookie/cache/header in session_start().

Hello,

This post is the continuation of a post which I initially opened 2 weeks ago on the Evolve Theme forum. I know, oops! This involves a core WordPress module. The previous post can be found here.

The problem occurs performing a PHP Include from a WordPress page to an external php page. Within that external page, I set a Session and validate the users WP credentials. The page errors out with”
‘Cannot send session cookie/cache/header’, (output started at /home/wordpress/wp-includes/class.wp-scripts.php:180) in /administration/index.php on lines 2 and 29.

Further more, I cannot perform any page redirects without receiving this error.

I have insured that no white space exists within the 2 files modified. The only modules modified within WP are:

• Functions.php in the child theme (added Admin Bar main/sub menu options)
• wp-config.php (added a variable to the end of the file)
• The addition of a new WP page.

The external standalone application being called is sound and has been used for several years but gets this error when called from within WordPress. I have done much more troubleshooting other than simply validating a potential white space issue in one of the modules.

One additional note. This implementation works on development box (Wampserver on Windows) but fails on production (Linux) box.

Any and all help would be greatly appreciated.

Thank you.