hey body: I just had the same problem but what I did is I downloaded the upgrade version 4 and it reinstalled the virtual platform. And then following the prompts for the upgrade installation it asked me for my key registration since i did not have one I simply apply for the 30 day free trial and problem solved. From this poing on you can either back up all your files or you can simply buy the new key registration. I love how fast and convenient this update is for my mac as well as for my windows 7.
Regards,
Henry.