Hi,
I get installer error in Joomla 1.5.23 trying to install FPSS, see details belowJInstaller::install: SQL Error. DB function failed with error number 1005
Can't create table 'jos_fpss_categories' (errno: 13) SQL=CREATE TABLE IF NOT EXISTS `jos_fpss_categories` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, `published` tinyint(1) unsigned NOT NULL, `ordering` int(11) NOT NULL, `language` char(7) NOT NULL, `params` text NOT NULL, PRIMARY KEY (`id`), KEY `published` (`published`), KEY `ordering` (`ordering`), KEY `language` (`language`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
SQL = CREATE TABLE IF NOT EXISTS `jos_fpss_categories` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  `published` tinyint(1) unsigned NOT NULL,
  `ordering` int(11) NOT NULL,
  `language` char(7) NOT NULL,
  `params` text NOT NULL,
  PRIMARY KEY (`id`),
  KEY `published` (`published`),
  KEY `ordering` (`ordering`),
  KEY `language` (`language`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8;
Component Install: SQL error or missing or unreadable SQL file. DB function failed with error number 1005
Can't create table 'jos_fpss_categories' (errno: 13) SQL=CREATE TABLE IF NOT EXISTS `jos_fpss_categories` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, `published` tinyint(1) unsigned NOT NULL, `ordering` int(11) NOT NULL, `language` char(7) NOT NULL, `params` text NOT NULL, PRIMARY KEY (`id`), KEY `published` (`published`), KEY `ordering` (`ordering`), KEY `language` (`language`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
SQL = CREATE TABLE IF NOT EXISTS `jos_fpss_categories` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  `published` tinyint(1) unsigned NOT NULL,
  `ordering` int(11) NOT NULL,
  `language` char(7) NOT NULL,
  `params` text NOT NULL,
  PRIMARY KEY (`id`),
  KEY `published` (`published`),
  KEY `ordering` (`ordering`),
  KEY `language` (`language`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8;

Did you check REQUIREMENTS paragraph at FPSS documentation?
In addition, make sure that you are trying to install the latest FPSS version...