Check of there is a robtest/tldtest remaining started on the media server, if you have used this command.
Either through the Console, Activity Monitor, Processes ... see something like tldtest, acstest ? depending on your robot type.
From command line, on the media server : vmps (from unix) or bpps (from windows).
Some activity locks access to your robot (assuming the configuration used to work and was not touch recently).
You need to kill the robtest if it's on. And remembre you are not supposed to run robtest during backup sessions.
