I am trying to upgrade from 2.4 to 2.6. I backed up my moodle folder and deleted the original. Copied the Moodle 2.6 folder into server. Copied back the config file. Ran update. It passed it's inital checks and showed plugins, without any issues. When I click on continue it started to Upgrading new version and showed System label on screen, nothing else except for a blank screen, no progress nothing. Any suggestions. This is my development server on a Windows Vista machine.