Go through Beckett's Quary to the right exit, that will put you in El Suderon. Run through El Sud to the only exit, and that puts you on the "Padres Back Beach". Darkheart is to the left, through a portico, in a tent.
Check the wiki maps here:
http://www.disneyonlineworlds.com/in...dres_Del_Fuego
Hope that made sense...