Looks like several users reported problems with installation and setup Tigase with PostgreSQL database. Apparently the installer does not correctly create database for the server.
http://www.tigase.org/content/510-b2512-beta1-jdbc-exception
Updated PostgreSQL (JDBC4) driver fixed this issue. New driver uploaded to SVN repository.
Looks like several users reported problems with installation and setup Tigase with PostgreSQL database. Apparently the installer does not correctly create database for the server.
http://www.tigase.org/content/510-b2512-beta1-jdbc-exception