[John Massey]

If you’ve filmed the shot at a higher frame rate than the project, maybe try right clicking on the clip in the bin and select source settings, then change the FPS setting to source, (or maybe it’s project, I can’t remember).

Fluidmotion needs rendering to play. Select the video track in the track selector on the timeline, Park the playhead over the clip, right click and select render at position

You could also try using the fit to fill effect on the clip. Then adjusting length of the clip in the timeline via a trim changes the speed of the clip, although it shouldn’t be any different to using time warp.