No, you are not allowed to apply for more than one MSc programme at Rotterdam School of Management (RSM). The RSM admissions office will always try to make you an alternative offer of admission for another MSc programme at RSM if your admission into the programme you applied for is rejected.
Note: Although you can't apply for multiple programmes at RSM, it is always allowed to apply for MSc programmes at other faculties from the Erasmus University Rotterdam (like the Erasmus School of Economics for example) next to your RSM application.