Code:
import flash.utils.getDefinitionByName;

var len:uint = 10;

for (var i:uint=1; i<=len; i++) {
        var s:String = "s" + i;
        var cr:Class = getDefinitionByName(s) as Class;
        var ss:Bitmap = new Bitmap( new cr());
        var obj:* = this["object" + i];
        obj.addChild(ss);
}