Flash says the code is on my second line, but I've done some reading and it says this error is mainly due to me trying to assign a value to a value, and I've looked back over my code, and I can't seem to find any instance of this.
Here is my code:
this.mc=new MovieClip();
addChild(mc)=("myButton1", this.DisplayOBjectContainer.numChildren());
myButton1.createEmptyMovieClip("buttonBkg", myButton1.getNextHighestDepth());
myButton1.buttonBkg.lineStyle(0, 0x820F26, 60, true, "none", "square", "round");
myButton1.buttonBkg.lineTo(120, 0);
myButton1.buttonBkg.lineTo(120, 30);
myButton1.buttonBkg.lineTo(0, 30);
myButton1.buttonBkg.lineTo(0, 0);
Thanks!