why the error?

actionScript on button


on (release) = function() {
_imageLoader.main_03.startFrame = _imageLoader.main_03._currentframe;
_imageLoader.main_03.gotoAndPlay(_imageLoader.main_03._currentframe+1)
_imageLoader.main_03.onEnterFrame = function() {
if(this._currentframe == this.startFrame+19) {
this.gotoAndPlay(11);
}
}
}

**Error** Scene=Scene 1, layer=content, frame=2:Line 1: '{' expected
on(release) = function() {

Total ActionScript Errors: 1 Reported Errors: 1

your getting confused with to different event syntaxs:-

on (release){
//whatever (use this one for this instance)
}

or

instance_name.release = function(){
//whatever