symbian^3 build not working on phone

[rocksvick]

i am developing game for symbian^3 device using carbide c++ .
i have self signed the build and when i try to install it on symbian^3 device i.e on nokia c7 it gives me this message.

certificate may not yet be valid,has expired or phone's date setting may be incorrect.

i dont know whats the problem with that.
please help

thanks

[Symbian_Neil]

Check that your device time is later than the system time on your computer.

[savaj]

As error message indicate, check validity of certificate and current date in your phone.