OK so I have read through the walkthroughs/forum postings about this quest and for some reason it's not working. Here's what's happening:
I am attempting to get to the 3rd level of the undermountain, and I have all the chains, each has already been placed at the corresponding pillar.
The pool is able to display six different colors for me.
However, each time I pull the corresponding chain a message appears above my head that says something like "you pull the chain but nothing happens"
Anyway if I managed to get all six colors right during the display, nothing happens. I am unable to open to door nor activate the pool. I have to hit the wrong pillars to start over again. When it starts over, it actually uses the SAME pattern very time, I have to reload or exit the level and reenter for the pattern to change (just making note of it bc I read that it is supposed to change each time you start over)
Also I read that there is a sound effect when you pull the right chain, I don't think there is one for me.. LOL and for the record I'm not color blind, and am indeed quite sure I should have completed the puzzle long ago. I'm about ready to give up on the game- just seeing if any of you lovely readers had any suggestions.
If I wait until the pool is done displaying colors and then begin to pull chains, it automatically fails and that little wyvern appears to fight. It appears to work best if I pull the chain at the time the color is displayed (easier with potion of speed) but then once I have pulled it for each of the 6 colors nothing happens!
Any Suggestions? I have already downloaded and installed the last game patch.
Please help, and thanks for reading!

OK so for whatever reason, I left it unpaused while I was typing my post, then tried the combination and it finally opened the door. I suppose I wasn't waiting long enough after the sequence? Not really sure, but I'm glad posting in this forum worked for me (just not like I thought it would!)
Thanks all, nothing to see here...