Can anyone tell me where config.php is called?

I have ckeditor and the ckfinder integration installed via php.. everything works great but I have one small tweak to make...

in the config.php file within ckeditor, I have set custom baseURL and baseDir locations for uploads and file browsing but there is one value from an outside script that I want to apply to it dynamically.

my path is basicly "/somefolder/somefolder/users_id/

users_id is the value I want to set dynamically. I have this available as a variable but the config.php must be called outside of the normal scope (in a function I would assume) because it does not recognize it.

Can someone tell me where the config.php file is called?

Hoping someone can point me to it.

Thanks in advance... Russ