Without proper system and version information as well as details about your project nobody can tell you anything.
Samurai is the internal name for the Roto Brush effect. You already have this effect when you install After Effects. This effect does not work in Premiere Pro. You can export an intermediate file from After Effects to Premiere Pro to get the Roto Brush results into Premiere Pro.
Samurai is the internal name for the Roto Brush effect.
That is excellent.