"Add Media" button not working when creating new post

I just ended up putting in define(‘SCRIPT_DEBUG’, true); to my wp-config.php and it solved it for me, but I have no idea about coding and just read it on a comment. I’m sure it’s not a permanent fix but…I’m using Custom Community theme and so…I don’t even know where to put it in in the file directory, as I tested it out on twenty twelve wp-config.php.

What is the difference between that CONSETENATE and SCRIPT_DEBUG?