求助，21点游戏DEMO打开报错，资源管理器一直显示"加载中…"，控制台异常信息如下：
Exception TypeError: Cannot read property ‘assetType’ of null
at i.Tasks.deepQuery (D:\Cocos\CocosCreator\resources\app.asar\asset-db\lib\tasks.js:1:11192)
at D:\Cocos\CocosCreator\resources\app.asar\asset-db\index.js:1:1671
at D:\Cocos\CocosCreator\resources\app.asar\node_modules\async\lib\async.js:945:13
at Immediate.q.process (D:\Cocos\CocosCreator\resources\app.asar\node_modules\async\lib\async.js:913:25)
at processImmediate (timers.js:374:17)