Is it a bug? Lord of Verminions

[Cold_Raven]

Where do I go to play that?

Gold Saucer

And can we play it vs an npc?

Yes. There are 24 single player "challenges" to get through, and when you beat the last one, you get a Twintania minion

or is it a pvp thing? or both?

Both.
You can also play vs. others with it's own sorta-kinda-Duty-Finder-like thing (must remain within the minion/chocobo area of Gold Saucer, World only, not Data Centre-wide).
There are also tournaments similar to Triple Triad tournaments.

Win 50 vs.-other-ranked-real-people battles (called "RP") and you get a Deepeye minion.
Get at least 10-wins in 4 tournaments and you get a Penguin minion guy.

As for the shield problem, I played twice in the past week and I was able to attack the shield just fine.
Maybe rebooting the game client might help? I dunno...

[Taliah]

I had the same problem, but i was able to fix it

Pls check if you own the minions used by the tutorial.
They can be bought at the capital cities for around 2500 gil. ( http://xivdb.com/item/6003/Kirschbomber-Pfeife )
After buying them i was able to complete the Tutorial