No i didn't copy it over, i don't want use that program .
Any reason for this? Unetbootin (or alternatives) are the right tool for this job.
If you've just transferred the files to your external HD your files should be there, but your system may not know to boot from the external rather than local HDD. Is the boot order correct for what you're attempting? (dd wil have the same issue)
Which Live OS are you using? (assuming BackTrack given forum topic), without using unetbootin you can boot the iso, then use the install
option, pointing the installer at the correct external HDD. (Make sure you pick the right option, making a mistake
hose your local system).
Hope this helps, but we'll likely need more info than you've provided to assist further if not.