You need to copy:
./packages/acs-core-docs/www/files/nsd-postgres.txt
into where ever your aolserver was installed, in my case is /usr/local/aolserver so I do this:
cp ./packages/acs-core-docs/www/files/nsd-postgres.txt /usr/local/aolserver/bin/nsd-postgres
then open the file and make sure the PATH and LD_LIBRARY_PATH variables are correct.
chmod a+x /usr/local/aolserver/bin/nsd-postgres
Now start aolserver this way:
/usr/local/aolserver/bin/nsd-postgres -t /path/to/your/config.tcl