If your system is installed on a Windows Server 2008 (64 bit) one thing to check is the Business Intellegence scheduled task. If the ‘Configure For’ is set to ‘Windows Vista or Windows Server 2008’ , try recreating the task again and set the ‘Configure For’ to ‘Windows Server 2003, Windows XP or Windows 2000’.

The Scheduled Task should now run and start refreshing the Cubes.