There is the slight possibility that you own a clone of the SoloSe (CloudBox 3). This one will only allow VTi 6 or OpenPli 4. If you are sure it actually IS a genuine box you may have a problem with the +5v USB support. You can easily check by putting a USB stick in the box and use the Media Player build in to see if it ‘sees’ the files. If not, your box is faulty. When yes, retry the files..
Use ZIP on a PC, the MAC variant poses problems..