Fatal error: Call to undefined method JException::getNullDate() in ... /installation/installer/helper.php on line 290

Errors:

• Fatal error: Call to undefined method JException::getNullDate() in installation\installer\helper.php on line 290
• Fatal error: Call to undefined method JException::getNullDate() in /installation/installer/helper.php on line 290

During the installation of an undergoing Joomla 1.5 project, I deliberately hit the browser's back button during the initial installation steps (as part of Joomla 1.5 testing, one of those "what would happen if's"). Of course, data has to be resent, thus hitting the back button during the install steps produces this error.

Dilemma:

How to proceed with the installation, or do a re-install of Joomla 1.5 ?

Solutions:

1. Create a new and completely empty file, name it as configuration.php and upload or save it to your joomla root directory (e.g. .../www/joomla-folder/ or .../htdocs/joomla-folder, etc.) replacing the previous configuration.php.

Then go back to the installation process of Joomla 1.5 (http://joomla-site/installation/index.php, or http://www.joomla-site/installation/index.php). You will then have to enter (or re-enter) the details as the installation proceeds. This is part of what they call a manual installation

In my case, the previous installation (that have gone wrong) had reached the "Install sample data", so I had to also drop/delete the initial database created in phpmyadmin (http://localhost/phpmyadmin/ or similar mysql admin tool) to give way to the second, fresh installation.

2. Installation should basically work then. If not, recommended further steps can be found here http://help.joomla.org/content/view/1945/302/

Hope this helps!