Address already in use

When starting the Isac Tutor, e.g. from Scala-IDE, then the login-window might disappear after some seconds raising the error gailed to contact as //localhost/BridgeRMI (creating RMI-Server on localhost: 1099) can not create registry: Port already in use: 1099; nested exception is: java.net.BindException: Address already in use (Bind failed)