Scene not moving

Im making this fps, and after the player clears each level, there is a intro scene to the next level, explaining to the player what he has to do in the next level.

Well, there was one level where the player has to go through a burning building. In that intro scene, I imported the same building and the flame effects, built an environment, and placed the camera at an appropriate angle so the player could see the building burning. When I load the scene in play mode, the flames do not appear. I tried agin, and then the flames appeared. I tested it again, and then it did not appear. Then it appeared. I do not get it.

PS I do not want to use backdrops, because I want the flames moving.

THX in advance!

Well it seems a bit strange that the flames keep showing up and then not showing and repeating that, but, assuming your fire is a particle system, make sure that on your particle system you have and Illipsoid Particle Emitter, Particle Animator and a Particle Renderer. Also, try and think about things that you might have accidentally done different on the times that it did an didn't work, and post back anything that you think might be causing it.