Error in phase of assigniment Action Script

Question

Hello Guys!
I created the following action script named "sketch.as" :
package
import flash.display.Sprite;
import flash.events.MouseEvent;
import com.adobe.images.JPGEncoder;
public class sketch extends Sprite {
public function sketch():void {
//this is your documentclass constructor
stage.addEventListener(MouseEvent.MOUSE_MOVE, moveCursor);
Mouse.hide();
function moveCursor(event:MouseEvent):void
    pencil.x = event.stageX;
    pencil.y = event.stageY;
var canvas_mc:MovieClip = new MovieClip()
addChildAt(canvas_mc, 0);
canvas_mc.swapDepths
function sketch()
canvas_mc.graphics.beginFill(0xFFFFFF);
canvas_mc.graphics.drawRect(0, 0, 600, 500);
canvas_mc.graphics.endFill();
canvas_mc.addEventListener(MouseEvent.MOUSE_DOWN, startDrawing);
canvas_mc.addEventListener(MouseEvent.MOUSE_UP, stopDrawing);
canvas_mc.addEventListener(MouseEvent.MOUSE_MOVE, makeLine);
function startDrawing(event:MouseEvent):void{
canvas_mc.graphics.lineStyle(1, 0, 1);
canvas_mc.graphics.moveTo(mouseX, mouseY);
canvas_mc.addEventListener(MouseEvent.MOUSE_MOVE, makeLine);
function stopDrawing(event:MouseEvent):void{
canvas_mc.removeEventListener(MouseEvent.MOUSE_MOVE, makeLine);
function makeLine(event:MouseEvent):void{
canvas_mc.graphics.lineTo(mouseX, mouseY);
sketch();
var serverPath:String = "";
function createJPG(m:MovieClip, q:Number, fileName:String)
var jpgSource:BitmapData = new BitmapData (m.width, m.height);
jpgSource.draw(m);
var jpgEncoder:JPGEncoder = new JPGEncoder(q);
var jpgStream:ByteArray = jpgEncoder.encode(jpgSource);
var header:URLRequestHeader = new URLRequestHeader ("Content-type", "application/octet-stream");
var jpgURLRequest:URLRequest = new URLRequest ( serverPath+"jpg_encoder_download.php?name=" + fileName + ".jpg");
jpgURLRequest.requestHeaders.push(header);
jpgURLRequest.method = URLRequestMethod.POST;
jpgURLRequest.data = jpgStream;
var jpgURLLoader:URLLoader = new URLLoader();
//jpgURLLoader.load(jpgURLRequest);
navigateToURL(jpgURLRequest, "_blank");
save_btn.addEventListener(MouseEvent.CLICK, saveBtnPress);
save_btn.addEventListener(MouseEvent.ROLL_OVER, saveBtnOver);
save_btn.addEventListener(MouseEvent.ROLL_OUT, saveBtnOut);
function saveBtnPress(e:Event):void
createJPG(canvas_mc, 90, "sketch");
function saveBtnOver(e:Event):void
Mouse.show();
pencil.visible = false;
function saveBtnOut(e:Event):void
Mouse.hide();
pencil.visible = true;
Lately I created a file .fla in the same root of the file .as naming it "sketch.fla"
When I try, in the Adobe Flash CS4 Professional screen, to assign to  ".fla" in the properties Publish my action script, the following message appears:
“A definition for the document class could not be found in the classpath, so one will be automatically generated in tha SWF file upon export.”
Obviously, it doesn’t function
Could somebody help me??

Answer 1

i don't understand, "When I try, in the Adobe Flash CS4 Professional screen, to assign to   ".fla" in the properties Publish my action script, the following message  appears:"
but i do understand that error message.  you need to assign the document class for your fla.  in the properties panel with the backstage selected, assign sketch in the class or document class field.