Nobody knows, how to hack nokia E72 with HelloOx2 ??

There is a better way of doing it. You can download a symbiam application signer from Internet and can also download certificates for your mobile. Then you can use the application to sign any symbian application using the certificates and can install it into your phone. The certificates are specific to your phone and its IMEI. You can search internet for it and you may find some site which allows you to get certificates for your phone.