"/equip range "Horn" "
Double check your caps, that can and will mess it up, IIRC, also make sure the item is in quotes and spelled exactly how it is in your inventory, caps and all.
EDIT: And if you're using windower scripts, then that's another ballpark entirely.
Edited, Aug 28th 2010 2:53pm by ElvaanTHF
THF on HNM attack in Binary. 10010110101