If Disk Doctor sees the disk, it quite certainly isn't the FW port.
Well: NEVER use Disk Doctor, btw. It's a bad, bad, bad tool that can do bad, bad, bad things to your harddrives. It has a history of bugs that turned a lot of users' data to garbage. Well, less than garbage, actually.
Instead: Use Apple's Disk Utility. Does it see the drive? Are there any volumes on it to be seen? If not, you can use Disk Utility to create some.