1. are you starting the server as root, either by using sudo or by starting as root user? Only root can use ports numbered under 1024 .
2. are you sure that all pieces of the old AOLserver are completely dead? Under Linux, run "ps auwx | grep nsd" and be sure that the old nsd has actually exited. You may need to use "kill -9 PID" where PID is the process ID of the old nsd , to be sure it is dead and gone.