I see several problems:
1. "/var/openacs-5.1.5/etc/config.tcl" should actually be "/var/SERVICE_NAME/etc/config.tcl". Once you do that (change the folders name to the service name, then you need to change the ownership of the folder and ALL the files inside to the user who owns the service. See the docs, it is there.
2. Once you succesfully complete the previous step, then you need to start the server under the user who owns the service if you are not creating this for production in port 80 like this:
Let's say my service is called "lgarcia", so to start I do:
su - lgarcia
password
/usr/local/aolserver/bin/nsd-postgres -t /var/lib/aolserver/lgarcia/etc/config.tcl
If for production in port 80, then you need to start the service as root and use -u USER_OWNER_OF_SERVICE and port 80 for it to work. For instance:
Again my service is called "lgarcia", so to start I do:
su -
password
%>/usr/local/aolserver/bin/nsd-postgres -t /var/lib/aolserver/lgarcia/etc/config.tcl -u lgarcia -g web -b 192.168.1.2:80
