I just installed Nikon Scan 3.14X under panther and it had no problem recognizing my Super Coolscan 4000 ED. The installation was on a Powerbook G4Ti. I did do a complete Erase and Install for my Panther Installation; not sure if that had anything to do with the success.
I did read some other report on macintouch of it not working with a Panther installation, however I can say that it did work fine for me. There is also another reader on macintouch that reports that it did work for him. Go Figure. Let me know if you have any more questions.