Is this a dual boot machine? Both windows and linux on the same box? If so, do you ever notice any problems with the external drives when windows is running? I'm asking, because I'd like to eliminate a hardware issue.
You showed me that these are 2 physically seperate external drives, /dev/sdg and /dev/sdh, correct? I was thinking that it might be a dbus issue. I do not know what system Windows 7 uses to handle usb connections/disconnections. I think Linux is using dbus, but I don't know much about how dbus works. If in fact it is an issue with dbus; I'm afraid I won't be of much help.