27 are 4 gates, they have to be opened with the levers I described.

At 16 => the door opens if you put a yellow and a red gem into the statue there. Click on it and an inventory will open. The red and yellow gems for this are at 14 and 3. The hole with 2 yellow gems and a lot of bones requite patience. Just grab in there about 13x, then you've got them. Chuck out the bones then.

http://www.kiya1.de/beyond/act4screens/Act4draggem0.jpg

The locked door at 11 is ok - you have to get the 2nd summoning quest. then Tax will give you key for this locked door.

As you used the rope downwards => you have been in the summoning level. Go up the rope and then take the door south. You're in this level then

http://beyond.divinedivinity.net/help/act4_academy_l2.htm

at number 2. Just go south and you meet Ankhumar.