(before Fall 2010, you had to activate three crystal stands at approximately the same time)
This unlocks the door to The Crown of Fire (where you meet Malistaire).
When I did this quest, I used the path through Dragon's Maw to access the Crystal Stand. I found that I can "sneak past" the two dueling circles in that area. When you get through Dragon's Maw, there is a door that leads to "The Great Spyre". (Look at your map. You are on the lower gray path.) Turn right and go to the "Crystal" stand. Press "x". This unlocks the door to The Crown of Fire.
Now you have to go back through the Dragon's Maw area again and return to the area where you defeated the Gurtok Demons near the elevator. The door to The Crown of Fire should now open for you.
(before Fall 2010, you had to activate three crystal stands at approximately the same time)
This unlocks the door to The Crown of Fire (where you meet Malistaire).
When I did this quest, I used the path through Dragon's Maw to access the Crystal Stand. I found that I can "sneak past" the two dueling circles in that area. When you get through Dragon's Maw, there is a door that leads to "The Great Spyre". (Look at your map. You are on the lower gray path.) Turn right and go to the "Crystal" stand. Press "x". This unlocks the door to The Crown of Fire.
Now you have to go back through the Dragon's Maw area again and return to the area where you defeated the Gurtok Demons near the elevator. The door to The Crown of Fire should now open for you.
Sorry if I confused you, but I hope this helps.
It could also be the other area. Hope you have fun. The animation is REALLY cool.