Hi, I'm totally new to processing & Supercollider

I finished installation of sc p5 & osc and I copied an examples and run it but it doesn't work.Error message is 'ClassNotFoundException : oscP5.OscPacket'. What is problem? Could anybody help me?

This is exmaple that I pasted.

import supercollider.*;

Synth synth;

void setup ()
{
   size(800, 200);

   // uses default sc server at 127.0.0.1:57110    
   // does NOT create synth!
   synth = new Synth("sine");
   
   // set initial arguments
   synth.set("amp", 0.5);
   synth.set("freq", 80);
   
   // create synth
   synth.create();
}

void draw ()
{
   background(0);
   stroke(255);
   line(mouseX, 0, mouseX, height);
}

void mouseMoved ()
{
   synth.set("freq", 40 + (mouseX * 3));
}

void stop ()
{
   synth.free();
}

yeah,

you need to install the oscP5 library too.
It is an oversight from this tuto.
have a good trip into sound