Same problem here. But I have found out that the updating works from within File Browser (the Backend one). However, if the Backend “File Browser” Window displays an Error-Message that the File “AdminGuiFilebrowser.php” cannot be found, it’s because that file is named AdminGuiFileBrowser.php (uppercase on the B) so you have to fix that too and correct the file name (another small bug in this Version).

I hope that at least gives an alternative to update files, while the main issue has not been solved yet.