Replacing header

Hi,

I have built a header with Greenshift that I would like to use instead of the default one.
The header template has a shortcode: [wp_reusable_render id=’74’]

Now I have unhooked the default header with this

add_action( 'after_setup_theme','tu_remove_header' );
function tu_remove_header() {
    remove_action( 'generate_header','generate_construct_header' );
}

and I have tried adding the shortcode with this

add_action( 'generate_header','example_function_name' );  
function example_function_name() {
    echo do_shortcode('[wp_reusable_render id='74']');
 }

but there must be something wrong in the PHP because it won’t let me save this. What am I doing wrong?
Thanks!