Calling in Custom Nav Menu

Firstly – Im not sure if Im posting in the correct area for this topic and my apologies to the moderators if it belongs elsewhere.

Im working on developing a custom theme for a client and have been using Thord Hedengrens Smashing WordPress Beyond the Blog (Second Edition) book as guidance. I’ve built my current theme off of his basic Notes Blog Core theme. Iv’e added to and shaved of appropriately from the theme to fit my needs.

Currently Im running into trouble attempting to call in custom menus into my template files. This process appears to be simple for all intensive purposes yet I still can’t get it to work properly? Here’s whats going on:

1) I’ve called in the proper custom menu in the functions.php file with the correct code, and name of specific menu. It appears in the Admin Panel.
2) I’ve used (what I believe is) the correct php tag ( wp_nav_menu (‘menu-name’) ) in the appropriate area of the template file where its intended to go – in this case a custom header I’ve created specifically for content pages.
3) I’ve Selected the appropriate menu from dropdown in the Menu’s section of the admin panel to be used.

The Result: It seems to spit out a subnav-menu sidebar widget in the intended navigation area??? This subnave widget IS called out in the functions.php. But it’s strange because the php tag in my header isn’t at all calling for that sidebar widget?

So I’m not quite sure whats going on? This SHOULD be relatively simple from what I understand? Any help would be GREATLY appreciated.

I’d be happy to give a link to the beta site if that helps?

Again – thanks much for any help!
Randy