Carrying this discussion over from the One-Page Checkout support thread.

Quote Originally Posted by jpda View Post
Have checked it again.
Removed both local directories and put both local configure.php files in their 'normal' directories (/includes/ and /admin/includes/, w/o explicit defines for logs. Thus forcing reading of these configure files.
Result: both debug logs were written.

Restored both local directories, put both local configure.php files in those local directories (/includes/local/ and /admin/includes/local/), w/o explicit defines for logs
And:
Restored both original configure.php files from the live site into their 'normal' directories (/includes/ and /admin/includes/).
Result: no log files!

Extra check: when I remove all configure.php files from /includes/ and /admin/includes/, leaving the local versions w/o explicit defines for logs, then debug logs will be written!

Conclusion?

Cheers,

jpda