I assume you are trying to create a custom class trainer?
From the "global class trainer" i think you want a class trainer that trains ALL classes?
You set "Npcflag" to 17, so it's a trainer with extra gossip options? have you linked the gossip in "World.npc_gossip"? And the text in "world.npc_text"?
You must also set "Trainer_Type" and "Class" and "Race"
for example 0 (class trainer) 1 (Warrior) 4 (Nelf)
In this case its a class trainer for Nelf Warrior's only.
You can leave "Race" empty so any race can train from the npc.
I also noticed how it seems to be impossible to create a "global" class trainer because in the field "class" you must enter the class that can interact with the trainer, i don't think you can set more than one class.