If you are using any Sparky based template in the versions of Joomla 2.5.17 and all later versions of Joomla 2.5 and got error "jhtml bootstrap not supported", deleting few lines of code in 2 files will help you to resolve this.

Edit file /templates/hot_template_name/index.php and delete this part

if (preg_match("/2.5/i", JVERSION)) {
JHtml::_('behavior.framework', true);
} else {

Finally, edit file /templates/hot_template_name/component.php and delete these 2 lines:

JHtmlBootstrap::loadCss($includeMaincss = false, $this->direction);

After making these changes in these two files, the error "jhtml bootstrap not supported" should be fixed.