E:failed to verify whole-file signature

[tch1981]

I was updating the CM9 for my d2g. and now it starts up to the cm9 load screen and stays there. i did the factory reset via power and x button. same result. tried to install again from sd card that way and i get an error saying

E: failed to verify whole-file signature
E: signature verification failed

anyone have any suggestions on what to do? please walk me through this!!!