Nowadays there are some application which are not upgrading their newer version for Symbian and Java mobile phones due to which such application will display “certificate expired” and won’t install. There are some applications which are really good and we want to install them but this error is problem for installing these application. 
I also faced lot problem due to this error but now I have got solution for this problem and these applications can be easily installed on mobile phones. This error is due to privacy concern of Nokia mainly in Symbian OS, which don’t allow you to install any application older than 6 months. There are two way which may help you to install these applications.
Method 1:
You will need to change the date of your mobile phone nearer to application release date. Of course you can change the date but I am going to show process just in case.
·         Go to Menu – Tools – Settings – General - Date and time – Date
·         Change Date nearer to the date application was released [ if you don’t have information of date it was released then keep changing it at the difference of six months]
·         The application should install when you set the date not more than it’s date of release
Method 2:
You have to change software installation to “All” from “Signed only”. In this case application is new but it won’t install as your setting is set to install only applications having valid certificates. This may cause application not to install as some application don’t have certificate attached to them.
·         Go to menu – Installation – App. Manager
·         Open Options – Settings
·         Open “Software installation”
·         Select “All”
Note: Process may vary depending on model of phone.
Now try installing application it should install. Hope it helps to solve your problem.