I must be missing something. How do you get in? I've spent 30 minutes looking for a key hole, running into the door and searching for levers....nothing. What am I missing? Help.

Did you talk to Kol?
(You don't HAVE to I think but it helps move the plot along)
Anyways, he tells you of a back entrance. Just go south from the temple main entrance and try to work your way through the woods towards the west. You'll probably have to swim a couple small pools of water on the way. Eventually, you should find some water and a wall with bars in it. That's where you can get in.

Also someone back at Valeia mentioned a back door (Tavern Guy?, or was it Harespia the Gypsy?). You need to chat to everyone you can along the way to get the answers to many of the problems you will inevitably face. For example, there is no way you will figure out how to get to the naga inside the temple without help. Hint - talk to the prisoner, if you can (hehe).

Of course you can always ask this board for help, or, even faster, use the search key. Almost every question from "How do I ....." to "Is ..... a bug?" has already been answered here (in triplicate, with fries on the side).