Only replying cause I once knew a girl named Melody.... /sighs and starts to reminisce
But in answer to your question, I would skip OPHcrack entirely and just use Katana. It has an OPHcrack install, as well as Kon-boot which just removes the password on the computer.
http://www.hackfromacave.com/katana.htmlJust plug your USB with OPHcrack back into the computer and Format it, then follow the instructions for installation on the link I posted above and you should be golden.
The reason I suggest this is because from what I remember of OPHcrack USB install it requires a few extra files to boot properly and IDK what they are, but katana has them all for you.
Cheers and GL cracking that BF's password