Hi reececropley,
In default it work only for the main site. For sub site, you have to create the table manually in the database. use below script to create a table. Please change the table name prefix accordingly.
CREATE TABLE wp_hsa_plugin (
hsa_id mediumint(9) NOT NULL AUTO_INCREMENT,
hsa_text text NOT NULL,
hsa_order int(11) NOT NULL default ‘0’,
hsa_status char(3) NOT NULL default ‘YES’,
hsa_date datetime DEFAULT ‘0000-00-00 00:00:00’ NOT NULL,
hsa_link VARCHAR(1024) DEFAULT ‘#’ NOT NULL,
hsa_group VARCHAR(100) DEFAULT ‘GROUP1’ NOT NULL,
hsa_dateend datetime DEFAULT ‘0000-00-00 00:00:00’ NOT NULL,
UNIQUE KEY hsa_id (hsa_id)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;