Now I got you.
In item.php is bug. Replace:
<?php if(osc_comment_title() == '') { _e('Anonymous', 'veronika'); } else { echo osc_comment_author_name(); } ?>
With:
<?php if(osc_comment_author_name() == '') { _e('Anonymous', 'veronika'); } else { echo osc_comment_author_name(); } ?>