get permalink of page children in loop

Using get_page_uri should do the trick:

<h2><a href="' . get_page_uri($pageChild) .'">' . $pageChild->post_title . get_the_post_thumbnail($pageChild->ID).'</a></h2>

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)