1) For being banned - he was obviously trying to connect to Admin with the Admin+ password, or vice versa.
2) If you want him to be able to change the GRS options, you'll need to give him remote access to the pc that is running GRS, which I presume is yours. This can be done most easily with Windows Remote Desktop (Windows XP/Server 2003) or with other programs like RealVNC for Java.
3) The players timing out is either a problem with the clients Internet connection or the servers Internet connection, or the server machine itself. If it is a very low spec running a constantly full 26 slot server, it could be killing the CPU / RAM very easily. Also check you have Server Patch 1 installed.