This issue was seen on power machines:
Start up during installation failed with:
Error initializing the PBS dataservice
Creating the PBS Data Service...
/bin/sh: /opt/pbs/default/pgsql/bin/initdb: not found.
Error creating PBS datastore
Check the logs in /usr/local/spool/PBS/server_logs for errors.
Installation of release complete
Checking the date immediately after installation:
Tue Apr 5 16:36:47 PDT 2016
And there seems to be an existing initdb file
rwxr-xr- 1 root system 158820 Apr 05 16:35 /opt/pbs/default/pgsql/bin/initdb