Hi,
You can do it your self by edit joomla.sql and sample_data.sql (in /installation/sql/mysql/ folder) then find this code:
CREATE TABLE IF NOT EXISTS `#__usergroups` (
...
Then change the ordering of "BTREE" word to correct like this code:
CREATE TABLE IF NOT EXISTS `#__usergroups` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT COMMENT 'Primary Key',
`parent_id` int(10) unsigned NOT NULL DEFAULT '0' COMMENT 'Adjacency List Reference Id',
`lft` int(11) NOT NULL DEFAULT '0' COMMENT 'Nested set lft.',
`rgt` int(11) NOT NULL DEFAULT '0' COMMENT 'Nested set rgt.',
`title` varchar(100) NOT NULL DEFAULT '',
PRIMARY KEY (`id`),
UNIQUE KEY `idx_usergroup_parent_title_lookup` (`parent_id`,`title`),
KEY `idx_usergroup_title_lookup` (`title`),
KEY `idx_usergroup_adjacency_lookup` (`parent_id`),
KEY `idx_usergroup_nested_set_lookup` USING BTREE (`lft`,`rgt`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=13 ;
Thanks