Loot Tables don't work on servers.

I used the loot table here (http://pastebin.com/raw.php?i=FLsH34DP) On a server, in "<World Name>/data/loot_tables/Mobs/tier/tier_one_mob.json" However summoning a zombie using 'Summon Zombie ~ ~ ~

{DeathLootTable:"Mobs:tier/tier_one_mob"}

' drops nothing when killed. I have also tried having the loot_tables folder in the folder the server is ran from as well as in a folder named "data" in the folder the server is ran from.