I apologize in advance for a duplicate post from WPMU Dev forum, but this is rather urgent as my users cannot see their admin panels. Here's what I'm trying to do and what I have done. I'm trying to create an editable homepage for each new blog. Many themes create a "home" page, but can't be edited by the user (unless you give them access to theme code). I had successfully created an "About Me" page in the wpmu-functions.php before under First Page code. So, I thought I could create a "home" page using the same code, then delete the home page creation code in the header of each theme.
On testing my changes, I created a new blog and the admin screen immediately went white. I'm also uable to login to the admin of any blog. I received the notice email that the blog had been created, but could got the white screen on login. So, I deleted the mysql tables for the new blog and returned the wpmu-functions.php code to the original. But I still get the white screen on login.
The error log shows:
PHP Warning: Cannot modify header information - headers already sent by (output started at /home/admin/public_html/wp-includes/wpmu-functions.php:4399) in /home/admin/public_html/wp-includes/pluggable.php on line 856
Here's the code at pluggable.php on line 856: