I used the skull key to enter the secret room off the kitchen before I went into the room with the iron floor and the skull key disappeared. Now I can't get into the room with the iron floor to get the serpent figurine... ...any ideas?

The key that opens the serpent holds is the Serpent Key that Kreug gives you. If that was the one you used and it disappeared, your only two solutions are:
1...reload a game prior to using the key or
2...search through some recent threads for the answers you get from using the serpent idol in the library and reading the book. It is possible to get through the whole temple without having to see it and read it if you find the answers here.

I have never known a key to work where it is not supposed to though.
: )
Moni

No, it worked where it was sopposed to. There is another skull lock in the kitchen, I used the key and opened the door, but the key disappeared. Now, even though it still says skull lock, I can click on it and the secret door opens, however I don't have a key for the door where I need it.

Too many levels and too many things done to start back that far.

The other thing I was wondering was could I start a new party in Ishad, go into the temple get the key, put the member with the key into my party and go open the door?

Excellent idea! I hope it works!
I don't see any reason why it shouldn't actually! You might have to bring them all back to town to the inn to make the switch.

Let us know if this works!

An after thought: Have you used Spirit Eye spell to see if it is on the flor somewhere?

If it fails, just remember you don't need the serpent idol as long as you have the answers to the Naga spirits questions and they are within a thread on the first few pages of this forum, so you won't have to spend the day searching for them!
: )
Moni