[LayaAir 2.0]tiledMap 官方示例都运行不了

tiledMap = new TiledMap();
        tiledMap.createMap("../res/dt.json", new Rectangle(0, 0, Laya.stage.width, Laya.stage.height), null);
 
调用后报错TypeError: Cannot read property 'split' of undefined
    at TiledMap.__proto.mergePath (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.tiledmap.js:257:31)
    at TiledMap.__proto.onJsonComplete (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.tiledmap.js:244:19)
    at EventHandler.__proto.runWith (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:1125:59)
    at Loader.__proto.event (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:882:28)
    at Loader.__proto.endLoad (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:14980:8)
    at Function.Loader.checkNext (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:15016:40)
    at Loader.__proto.complete (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:14968:34)
    at Loader.__proto.onLoaded (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:14933:9)
    at EventHandler.__proto.runWith (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:1125:59)
    at HttpRequest.__proto.event (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:882:28)
TypeError: Cannot read property 'split' of undefined
    at TiledMap.__proto.mergePath (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.tiledmap.js:257:31)
    at TiledMap.__proto.onJsonComplete (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.tiledmap.js:244:19)
    at EventHandler.__proto.runWith (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:1125:59)
    at Loader.__proto.event (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:882:28)
    at Loader.__proto.endLoad (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:14980:8)
    at Function.Loader.checkNext (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:15016:40)
    at Loader.__proto.complete (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:14968:34)
    at Loader.__proto.onLoaded (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:14933:9)
    at EventHandler.__proto.runWith (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:1125:59)
    at HttpRequest.__proto.event (file:///C:/Users/Administrator/Documents/myLaya/Hello/bin/libs/laya.core.js:882:28)