Properly embed javascript into WP (using function.php) – doesn’t work?

By default, the jQuery script is loaded in no conflict mode. I noticed that you have in you header.php the following code:

<script type="text/javascript" src="https://wordpress.stackexchange.com/questions/27986/<?php bloginfo("template_directory'); ?>/js/jquery-1.4.2.min.js"></script>

Adding jQuery like this, will override (if the page works) the wp_enqueue_script(‘jquery’).

If you load jQuery like this, you need to activate the noConflict mode, as explained here.

My suggestion is to load your scripts one way, or via wp_enqueue_script or by including in the html header tag. Using both is tricky.

Hope it helps.

Domingos