If yours is like the 100 that I used to own, the secondary burn chamber trough is all one piece. It's some sort of high temperature cast/molded fiberboard that protects the metal from the high temperatures of gasification. I believe they glue it in with high temperature mortar. I guess the only advise that I'd give you would be to reposition the bricks on the floor of the primary burn chamber to move the nozzle toward the front of your stove about the thickness of two bricks to keep the high temps away from the bare metal. It should be fairly easy to make a snug fitting "U" shaped heat shield out of 12 0r 14 gauge metal to go in it's place until you can get the new part. You should be able to install it from inside the primary burn chamber by pulling out the bricks on top of the affected area.
I cleaned mine out weekly, and even though it was only a year old, I sometimes got a bit too aggressive and chipped out a few small pieces when cleaning out that area.
They should have made that piece out of the same refractory material that the bricks are made from.
The heat shield on the inside of the primary burn chamber on the right side looks to be made of the same material and mine was half worn out after one year.