it is odd, indeed. Could you give us some more info about these problems?
Are you using CPU or GPU for the fire/render?
Are you using custom MXM materials or embebed Characters presets?
Could you please explain a bit what do you exactly mean with "and appear to emit when I have not selected this"? When you select the objects that have these materials assigned in Sketchup, they look like an emitter instead of showing the texture in Fire?
Thanks in advance.