Hi,
The problem could be with the location of the pid file. Check your logs to see if AOLServer could create the PID file. If it can't, restarting aolserver via nsd will not be possible.
If there is a problem there is a parameter in the config file for pointing the file to somewhere suitable (where permissions are favourable).
using daemon tools will obviate the need for the above solution as no pid file is created.
Regards,
hafeez