<?php $z= \"DELETE * FROM new_post WHERE id_topicu='\".$_GET['id_usun_topic'].\"' \"; ?>
Wkurzyłęm się i zrobiłem tak:
<?php $z2 = \"SELECT * FROM new_post WHERE id_topicu='\".$_GET['id_usun_topic'].\"' \"; $z= \"DELETE FROM new_post WHERE id='\".$t['id'].\"' LIMIT 1 \"; } ?>