EJB's use RMI over IIOP, but if you use "Standard"-RMI you use RMI over JRMP. So you can take any Java (not J2EE) book covering RMI to learn the fundamentals.
RMI is a technology, JRMP and IIOP are protocols. So the technology is the same, but the protocols differ.
I think the instructions in the assignment regarding RMI over IIOP will confuse most candidates, because it looks like something, you have to take care for, but the best thing is not to care and just use RMI (which is RMI over JRMP under the covers).