Query OS X as to Contents of Folders and Attached Drives

I work in a high school iMovie lab. Students move from station to station and transfer their files using FireWire drives as well as storing their files on the drives overnight. Several students’ projects may be on the same hard drive at the same time. I would like to be able to have an AppleScript that will display on my screen the contents of the FireWire drives and a specific folder on the startup disks

A script like the following gives me the raw data I want (for one machine):

tell application “Finder” of machine “eppc://username:password@machine.local”
set theList to list disks
repeat with aDisk in theList
if ((offset of “Macintosh HD” in aDisk) = 0) then
set theFolder to “:”
else
set theFolder to “:student:
end if
list folder file (aDisk & theFolder)
end repeat
end tell

But the script doesn’t work if the computer has a FireWire drive attached but no one is logged-in – when the log-in window is active but the Finder is not running. I get an Execution Error : “Finder got an error: Cannot find process on host”. Is there another application I can call or do I need to call a UNIX script at that point.

Thanks.