I get this to and have found the same - start Dump1090 & planeplotter first and no problems,do the reverse and radarbox refuses to start.I have also noticed that if radarbox is running and I then try to start Dump1090 for planeplotter the program just flashes up on the screen and then dissapears which suggests to me that there is some sort of confliction between the two programs, however I'm no computer whizz so may be wrong.
Steve