I don't know much about time remapping but I have used it long enough ago to have forgotten what ever I might have known.
I did remember setting Layer/time/timremap, but when I select a layer and try to do that the `remap' menu item is unavailable (greyed out). So what might cause that to not be available.
Its a still image layer where I used the CCScaterize effect. Does that prevent timemapping?
from the "Time-remapping" page:
"Still-image layers cannot be time-remapped."
What are you trying to accomplish? Time remapping doesn't make sense for a still image.
If what you're trying to accomplish is remapping time on the result of the CC Scatterize effect, then precompose the layer with the effect and use time remapping on the precomposition layer.
I recommend that you begin here: