I'm trying to run the following code to export some mysql data as an CSV/excel file, but I keep getting a "Cannot modify header information - headers already sent" error.
I've checked the offending file (wp-admin/menu-header.php:114). It's a core WP file and it seems fine to me. No extra spaces at beginning or end. I even tried re-installing it. Can anyone take a look at this and let me know what I could try?