Hi, thanks for reviewing.
The error you mentioned is unimportant, try to do this once again:
as user ec2-user:
sudo su postgres
pg_ctl start -D /pgdata
(watch the output)
and after that:
sudo su - dspace
cd dspace-1.8.2-release/dspace/target/dspace-1.8.2-build/
/usr/local/bin/apache-ant-1.8.3/bin/ant fresh_install