I'm in the process of backing up large chunks of raw and rendered video media components to some FireWire drives. Unfortunately, I am not being allowed to transfer any media that contains a forward slash (I'm given a message that says that my files contain characters that cannot be used, and that's the only common character), and I need to see if anyone knows of a reason or a workaround. I have MANY elements that contain the forward slash, due to how my editing application names them when rendering composites.
Did you format the drives using the Disc Utility? It sounds like they're still in whatever format the company shipped them as. You should re-format them as Mac drives and then try to copy the file again.