Notice: Undefined index: DBtype in /is/htdocs/wp1234567890/www/installation/installer/models/model.php on line 764
Fatal error: Call to undefined method JException::getNullDate() in /is/htdocs/wp1234567890/www/installation/installer/helper.php on line 290
I have error above while installing Joomla 1.5, why and how to fix it?