javascript Fehler: jQuery is not a function WP 2.8.2

has anyone an hint?

i found this temporary solution on 1 post
its not useful for me
you try
may it work for you

WordPress 2.8 includes a concatenation of scripts and CSS. This puts the quality of these scripts at a higher level than before.

The temporary solution is to place it in the wp-config.php one of these two values :
define(‘CONCATENATE_SCRIPTS’, false );
or
define(‘SCRIPT_DEBUG’, true);