I cant start the map. There a error something like "...material_flamethrower_not_found"... can someone help me please? I really want to play this map. Ty

I have a problem with the easter egg. I play solo and at the step where i need to check the dead zombies for the code, i only get 3 letters of the code. I checked evers body. I think one of the letters was invisible when i chekced. Or i cant search a body. Did someone had the same problems? Is there a dead body guide/list?
 
Anyways i did the easter egg before, its a awesome map. Much better then some of the offical Cod zombie maps.
 
Btw. the ray gun mark 2 is ooovvver pooowered. I killed the giant robot with 3 hits and everything other is one hit, even in round 48.