system seems to get "stuck" for a while then continues

    if you have any non-rt transitions in the timeline, make sure show render image thumbnail in timeline is not checked in the view menu. also check for irq conflicts.

    "stop playback. frame drop has occurred." during playback

    this is the warning message shown when stop playback at frame drop is checked in the settings menu.

    this means that there are too many effects for the system to keep up with. render transitions and/or filters until you can play the timeline back normally.