Whenever u try to install an application (E. g. theme, game) to your Nokia device u might get an error message: "Installation security Error. Unable to install" or "Certificate may yet not be valid, is expired or phone's day settings may be incorrect" If you get such an error message, please set the device date to before 12.6.2007 (or for some applications maybe even earlier), and then this error doesn't appear and installation continues normally. After installation you may set date back to current date. If this does not help then TOOLS>APP MGR>OPTIONS>SETTINGS>SOFTWARE INSTALLATION and changed it from SIGNED ONLY to ALL.
