I had the same problem with my Fuze: Hardy Heron just couldn’t see it nor did it charge. I found the solution here ([ubuntu] how do I make my sansa fuze mp3 player work on ubuntu? - Page 3).
Basically run the following two commands:
sudo modprobe -r ehci_hcd
sudo modprobe ehci_hcd
As soon as they are run, the Fuze starts charging and the file browser shows up.
