dotmagic

You have some obviously mistakes in your code. It really sucks you blame other peoples and her (free!) work if you don’t even know the basics.

<?php if(function_exists('chi_get_header_image_url')) { chi_get_header_image_url(); } echo chi_get_header_image_url(); ?>

This will work aslong u enabled the plugin, but you call the chi_get_header_image_url() function twice and the first is ignored because you don’t output the returning result.

Just do the following and it won’t throw a error if the plugin is disabled:
<?php if(function_exists('chi_get_header_image_url')) { echo chi_get_header_image_url(); } ?>

The shortcode is only to customize the output of the header, its not a replacement for the PHP Code!

You place the code in your template where you like to output the HTML Image Tag. Thats all.

Enable debuging to get a more verbose output. The problem is certainly in your theme.

I have no idea why so many say its broken with 3.4.x.
I’m using it with WP 3.4.1 and it works fine. Anyway, you can disable the plugin and compile the .less file to .css, then change the line in funcions.php to include it in your theme, thats all.

I use Simpless for compile the less file. Once you know about less you won’t miss it anymore ??