wpg2 - [help!] header already sent error in Wordpress

First of all, thanks for great program.

I am using wp and it sort of works.
However, In some cases, this error occurs.

****************************************************
Warning: Cannot modify header information - headers already sent by (output started at /home/hosting_users/khp/www/wp/wp-content/plugins/wp-gallery2/g2embed.php:443) in /home/hosting_users/khp/www/gallery2/modules/core/classes/GalleryPhpVm.class on line 124
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This happens
1. When I click display mode:admin/guest at the right-bottom side.
2. When I click structural category at the left-top.(Under Daniel Park) -> For example, let's suppose it is like this, Gallery>gallery>landscape>img5908. If I click any of these, that error happens.
3. Site admin, if I click save or reset after some changes, same things happen.
You can visit 'photo' in my menu.
(This is my webpage. http://khp.cafe24.com/wp)

and this is 443 of my g2embed.php

//-------------------------------------------------------------------------------------------------------
// Function: Wordpress Image Frames
// Parameters: None
// Returns: None
//-------------------------------------------------------------------------------------------------------

function g2_imageframes() {
global $g2_option;

$wp_siteurl = get_settings('home').'/';

echo '<link rel="stylesheet" href="'.$wp_siteurl.$g2_option['g2_path'].'main.php?g2_controller=imageblock.ExternalCSS&amp;g2_frames='.$g2_option['g2_sidebarblockimageFrame'].'"/>';
echo '<link rel="stylesheet" href="'.$wp_siteurl.$g2_option['g2_path'].'main.php?g2_controller=imageblock.ExternalCSS&amp;g2_frames='.$g2_option['g2_sidebarblockalbumFrame'].'"/>';
echo '<link rel="stylesheet" href="'.$wp_siteurl.$g2_option['g2_path'].'main.php?g2_controller=imageblock.ExternalCSS&amp;g2_frames='.$g2_option['g2_postalbumFrame'].'"/>';
echo '<link rel="stylesheet" href="'.$wp_siteurl.$g2_option['g2_path'].'main.php?g2_controller=imageblock.ExternalCSS&amp;g2_frames='.$g2_option['g2_postimageFrame'].'"/>';

}

//-------------------------------------------------------------------------------------------------------

I read this article,
http://gallery.menalto.com/trip_search?keys=header+already+sent+tids%3A63
but [i]I couldn't find the answer.

Please help. Thank you.

Thanks for fast answer.