Why does the door open the opposite way it's supposed to?

I am having a problem with a door. When the player passes the Group Test and doesn't die, the door opens but it opens the opposite way (Lengthwise). I was wondering why this is happening? Below you can find the Model AND Script.

-----Door Open-----
                    for i = 34, 0, -1 do
                        a.CFrame = CFrame.new(a.Position.X, a.Position.Y, a.Position.Z+0.1)*CFrame.Angles(0, math.pi/2,0)--The direction it opens in, change math.pi/2 to /1 to change the orientation of the doors
                        b.CFrame = CFrame.new(b.Position.X, b.Position.Y, b.Position.Z-0.1)*CFrame.Angles(0, math.pi/2,0)
                        wait(0.05)
                    end

-------------------
                    Wait(2.2)
                    Screen.Texture = "http://www.roblox.com/asset/?id=121680038" --Default
----Door Close-----
                    for i = 34, 0, -1 do
                        a.CFrame = CFrame.new(a.Position.X, a.Position.Y, a.Position.Z-0.1)*CFrame.Angles(0, math.pi/2,0)
                        b.CFrame = CFrame.new(b.Position.X, b.Position.Y, b.Position.Z+0.1)*CFrame.Angles(0, math.pi/2,0)
                        wait(0.05)
                    end

Model: http://www.roblox.com/Group-Only-Door-item?id=155484773