Neither Banshee nor Rhythmbox will see files on Creative Zen. Right Clicking on Zen Player and selecting "properties" causes both Banshee and Rhythmbox to exit.
All MTP plugins & libraries seem to be installed.
This worked perfectly on 10.10.
Issue replicated on several 11.10 installations on Acer Aspire desktop, Acer 5552 Laptop and Panasonic CF52 laptop.