[wp-hackers] JavaScript related functionality failure on some admin pages. 3.5.1

[Haluk Karamete]

On 3.5.1 installs, ( and I got two of them ), the admin area JS actions (
such as the "Screen Options" or the "Help" pull downs and a whole bunch of
more functionality that relies on DHTML effects) all fails.

To troubleshoot the problem, I checked the JavaScript console ( chrome
developer tools ), and I saw a 404 being reported in there.

GET .../wp-admin/*load-scripts.php*
?c=1&load%5B%5D=admin-bar…alog,wpdialogs,wplink,wpdialogs-popup,wp-fullscreen,media-upload&ver=3.5.1
404 (Not Found) post.php:41

And this 404 comes up only on some pages at the admin interface.

For example, when adding a new post ( using the /wp-admin/post-new.php ),
there is no 404 issue and thus no js issues. Everything works like a charm.
But once the post is published and the /wp-admin/post.php responses back, I
get that 404 back again and that's when all the js issues are back.

I don't know what's causing this, but the following one-liner in the
 wp-config.php totally fixes it.

*define('SCRIPT_DEBUG', true);  *

which is not recommended to keep it on a production site.

So I got this dilemma now. What do I do?

To eliminate the problem, I not only switched our current theme to
the TwentyEleven( to see if theme is the culprit ),  but no, it wasn't.
Symptoms were the same with TwentyEleven.
I also deactivated all the plugins one by one but no luck... this did not
help neither.

So to get going, I had to leave the SCRIPT_DEBUG option on...

But, what's your advise for getting rid of this issue without the
SCRIPT_DEBUG being TRUE?

And out of curiosity, what is it with define('SCRIPT_DEBUG', true); that it
magically fixes the problem?