My default dnn file manager has a bug. I am unable to view the files inside any folder other than the root, I cannot create folders, I cannot upload files. This problem doesn't affect the other portals except the (0) portal. The Host File Manager has the same failure. Portals (1) and (2) File Managers work.  
Can someone tell me if you might have seen the javascript error that follows and possibly suggest where to begin troubleshooting.
The error is: dnn.controls.controls[...].selTreeNode is null or not an object
Default.aspx Line: 642
Code: 0