Ah! Different problem than mine then. Are your readings fluctuating, or just off? You'll want to calibrate any TC/amplifier combination before trusting their output. Put it in ice water and boiling water.
It took me quite a while to get solid readings from my TCs because of ground noise. Eventually fixed by eliminating a ground loop or two. That was with commercial pyrometers, before I went Arduino. The photo of your probe almost looks like it could be ungrounded.