1. RCS is running correctly on the server machine ( localhost or other location). Try restarting RCS once if feasible.
2. The IP address and port specified for RCS is correct ( check ZMASTER.EDM present inside lib folder for these details)
3. You can access the server machine both using IP and hostname ( try the ping utility).
4. RCS has not exceeded the task limit. THis means that the number of allowed concurrent connections to RCS is not matching with the actual load on the server. Check EDMPROF.dat file for the settings. The RCS logs will clarify further and also the packager log.