Yes, it works if I use a toothpick to selectOh noes! Does it still work in its present state? It most probably would be cheaper to find a replacement camera than a part/getting it repaired/trying to find a replacement back.
I've seen that happen to a few of the F/N series cameras, which is why I lock mine in the center spot position and leave it alone.

Thanks for your response. I'll just cover it with a little foam for the moment.Buy a parts camera. Even if you did find the part, it might be upwards of $20.
I just checked and it seem that button is unique to the N80/F80. I also discovered another advantage of the N55...no electronics in the back to break; the N55 does not have this button on the back.