When you get the "atm6124.Sys" device in Device Manager, are the drivers installed properly? It sounds like you may be getting the USB drivers instead of the CDC drivers there... (\USB\ARM0 instead of COM#).
No, I didn't do this - I let Windows automatically select the drivers. Which drivers should I point it to?
Have you tried right-clicking on the device and manually selecting the SAM-BA CDC drivers (browse...)? Or "uninstalling" the drivers and then trying to load them from Windows Update instead?
Again, I'll see if I can point it at a different set of drivers - I just need to know which ones are the right ones.
Also, are you running Windows XP, Vista or 7? 32-bit or 64-bit? If you have a copy of Windows XP (or Windows XP Mode on Windows 7), it may be easiest to reflash there instead.
I'm using Windows XP, 32 bit.