Do you have the tables in your database? The table names are wp_PO_post_plugins, wp_PO_groups, and wp_PO_url_plugins. If you don’t then please run these sql commands on your database and let me know what errors you get.
CREATE TABLE wp_PO_groups (
group_id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
group_name varchar(255) NOT NULL default '',
group_members longtext NOT NULL,
PRIMARY KEY PO_group_id (group_id);
CREATE TABLE wp_PO_post_plugins (
post_id bigint(20) unsigned NOT NULL,
permalink longtext NOT NULL,
disabled_plugins longtext NOT NULL,
enabled_plugins longtext NOT NULL,
PRIMARY KEY PO_post_id (post_id);
CREATE TABLE wp_PO_url_plugins (
url_id bigint(20) unsigned NOT NULL auto_increment,
permalink longtext NOT NULL,
children int(1) NOT NULL default 0,
disabled_plugins longtext NOT NULL,
enabled_plugins longtext NOT NULL,
PRIMARY KEY PO_id (url_id);