Warlock Spell: Summon Felsteed

When I hit level 20 I went to my trainer and clicked through the spells I had available in order to learn them all. When Summon Felsteed came up I clicked learn and nothing happened. When I closed the trainer's window and re-opened it the spell was no longer available. The problem now is that I do not know the spell and I cannot learn it. Is this a bug anyone has experienced or knows about?

This is a Mangos server 3.3.5a
Winkdogs repack
I am a warlock, and I have the riding skill

Kushiel