Closed Issue: Error when browsing for files [4393]

I am getting the following error when using the "browse server" option with a user in the Administrator group. (Host account works OK).
 
Using DNN 5.2, WatchersNET provider 1.10.01
 
Server Error in '/' Application.
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Value cannot be null.
Parameter name: child
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
 
Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: child
 
Source Error:
 
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
 
Stack Trace:
 
 
[ArgumentNullException: Value cannot be null.
Parameter name: child]
System.Web.UI.WebControls.TreeNodeCollection.AddAt(Int32 index, TreeNode child) +1159923
System.Web.UI.WebControls.TreeNodeCollection.Add(TreeNode child) +13
WatchersNET.CKEditor.Browser.Browser.RenderFolder(FolderInfo folderInfo) +243
WatchersNET.CKEditor.Browser.Browser.RenderFolder(FolderInfo folderInfo) +231
WatchersNET.CKEditor.Browser.Browser.FillFolderTree(String sPath) +299
WatchersNET.CKEditor.Browser.Browser.Page_Load(Object sender, EventArgs e) +1292
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +50
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627