Make sure {nl} is set as a location. You can try this
every 25 seconds:
if {gens} is true:
if {nl} is set:
set {_loc} to {nl}
add 0.5 to y-coordinate of {_loc}
drop a nether brick item named "&6Dark Copper&f" with mending 1 with hidden enchantments at {_loc}
Send any errors