There is always hope, but you need to follow the OP carefully.
If you are a windows user, you need to setup an usb storage stick in order to boot ubuntu (or even better) the fireISO (see the unlock thread for mantis), because the procedere from the first post will only work on linux. You also need to open up your fireTV box and you would need to short a special point on the mainboard, without to damage anything of the small smd parts. It's best if there is third hand arround if you do the shorting...
There are a few videos on youtube, at least for fire sticks, procedere is almost similar.
About your error, I guess a format data will fix it.