I got to the metal door before the maze section but could not get the statue to open its mouth. I even went to a walkthrough and did the same thing with the stones but it would not work. It is the GOG version of the game and I was following the partner path.

So that is the scene after Sophia got kidnapped? You have to turn the stones by 180 degrees (in the dialog book, there is a sentence that only the differently thinking/oriented (?) people got in).

Having played Fate Of Atlantis countless times, I can say that from my experience, sometimes the stone disk puzzles are glitched. By that I mean that sometimes you could swear you have the right combination of symbols, but the door refuses to open or the game refuses to progress, when that happens, I found out that sometimes the solution is to try opening the door after rotating all three symbols by 90°, 180° and lastly 270°. Most of the time, that solved the problem and when it didn't, that was because I had one of the symbols wrong in the first place.