Isn't that the festival that has Hammerfall? Any festival with hammerfall can never consider themselves prog. Nothing against hammerfall, but come on, it's like booking Leaves eyes.... Oh no, they have that too..... Well then, eeeehm..... Delain.... Oh noes, that too...... Well, bigger name.... Accept. No shit sherlock, they even have Accept?
Seriously, you wouldn't want to call those bands progressive, now would you? That's like saying Yngwie is progressive.
Ps. No Yngwie hating, love the guy, but he's about as prog as apple pie.