Error on restoring backup files after reformatting OS

Hello Everyone,
I had to format one of my machines completely due to some security reasons. I had taken a full back up of my account details as .grv file on USB hard drive.
Now when the machine is formatted and has Windows XP installed already, I am trying to restore the backed up files. When I try to restore my groove back up it says my account credentials are old.
It hardly took a few hours to clean the machine and install it back again.
Please help.
Saved account for Bil Simser
Saved account for Bil Simser is too old and cannot be installed. Please import a more recently saved version of this account.
