Trouble with user_register hook

Hi,

I’m trying to develop a small plugin, I have some test code written but it’s not working as expected.

Here is my test code:

add_action(‘user_register’, ‘modify_user_info_GMP’, 10, 1);

function modify_user_info_GMP( $user_id )  {
	update_user_meta( $user_id, 'first_name', 'First1' );
	update_user_meta( $user_id, 'last_name', 'Last1');
}

According to my understanding of the docs this should work, but it doesn’t. I’ve tried testing with a delay() as well and it looks like this function never gets called. The plugin file calls other hooks that work just fine.

Any ideas?

using WP v 3.1.3