Expired Certificate error is very easy......To Solvin....
Now go to Menu >Settings
In settings Find Date & Time
Set your Year to “2006″. Because some applications are certificated for 2005-2006. After setting your Year to 2006 install the application who gives certificate error
Finish your installation and you can set your current date back:)
Now go to Menu >Settings
Set your Year to “2006″. Because some applications are certificated for 2005-2006. After setting your Year to 2006 install the application who gives certificate error

