I got the answer. Problem was with proper merging in includes/templates/MYTEMPLATE/common/html_header.php

After replacing this file with html_header from css js loader, I had to add little line of code just before closing tag ?> :

PHP Code:
if (COLUMN_WIDTH == '0') {
    echo 
'';
} else {
    echo 
'<link rel="stylesheet" type="text/css" href="' $template->get_template_dir('.css',DIR_WS_TEMPLATE$current_page_base,'css') . '/' 'responsive.css' '" />';

After this everything works just fine!

(Before that, I tried to include all code from new and old html_header, but my css's was loaded twice this way slowing down my site)
Cheers, thanks for help!