我使用Unity3d Facebook SDK运行场景，在下面的控制台中加载了dll异常，我不知道如何修复它。
Console Log
Using SDK 6.0.0, Build 140805.da738911cf62c00
loading dll: https://integrated-plugin-canvas-rsrc.fbsbx.com/rsrc/unity/lib/sdk_6.0/CanvasFacebook.dll
Uncaught exception in async net callback: Object reference not set to an instance of an object
at UnityEngine.GUISkin.GetStyle (System.String styleName) [0x00000] in <filename unknown>:0
at UnityEngine.GUIStyle.op_Implicit (System.String str) [0x00000] in <filename unknown>:0
at UnityEditor.ProjectBrowser.InitSearchMenu () [0x00014] in /Users/builduser/buildslave/unity/build/Editor/Mono/ProjectBrowser.cs:471
at UnityEditor.ProjectBrowser.AssetStoreSearchEndedCallback () [0x00000] in /Users/builduser/buildslave/unity/build/Editor/Mono/ProjectBrowser.cs:499
at UnityEditor.ObjectListArea+<QueryAssetStore>c__AnonStorey2C.<>m__3A (UnityEditor.AssetStoreSearchResults results) [0x00356] in /Users/builduser/buildslave/unity/build/Editor/Mono/ObjectListArea.cs:406
at UnityEditor.AssetStoreResultBase`1[Derived].Parse (UnityEditor.AssetStoreResponse response) [0x000fc] in /Users/builduser/buildslave/unity/build/Editor/Mono/AssetStore/AssetStoreClient.cs:89
at UnityEditor.AssetStoreClient+<SearchAssets>c__AnonStorey41.<>m__6A (UnityEditor.AssetStoreResponse ar) [0x00000] in /Users/builduser/buildslave/unity/build/Editor/Mono/AssetStore/AssetStoreClient.cs:751
at UnityEditor.AssetStoreClient+<WrapJsonCallback>c__AnonStorey40.<>m__68 (UnityEditor.AsyncHTTPClient job) [0x00012] in /Users/builduser/buildslave/unity/build/Editor/Mono/AssetStore/AssetStoreClient.cs:624
External Call: IntegratedPluginCanvas.isJSOnly();
External Call: IntegratedPluginCanvas.getLocale();
External Call: u.getUnity().SendMessage('FacebookJsBridge', 'OnUrlResponse', location.href);
External Call: window.fbAsyncInit = window.fbAsyncInit || function () { FB.init({"appId":"1595588810705711","cookie":true,"channelUrl":"/channel.html","frictionlessRequests":true,"version":"v2.0",hideFlashCallback: onHideUnity}); fbOnInitWithStatus(); };if(!document.getElementById('fb-root')) {
var fbroot = document.createElement('div');
fbroot.id = 'fb-root';
var body = document.getElementsByTagName('body')[0];
body.insertBefore(fbroot, body.children[0]);
}
....(java script code skip)
External Call: IntegratedPluginCanvas.logVersion("6.0.0", "140805.da738911cf62c00");
FB.Init completed: Is user logged in? False