That message indicates the machine is already running a process or has a session pending. Note that he default view in Control Room is 'today' and a pending session created earlier will not be visible at first. BP can run multiple processes on the same machine but only if the 'Run Mode' of the objects used by the processes are in agreement. Run Mode is set on the Initialise page of every object and can be set as Exclusive, Foreground or Background, and only certain combinations of these enable parallel processing. For example, if a process uses and Exclusive object, no other process can run on the same machine at the same time. Two processes using only Background objects can run in parallel.
