Whenever I try to view my Sansa Clip with amarok 2.1.1, it says I have 0 tracks on it. However If I go into the mp3 player via a file browser, I can see all the music on there and transfer to it. Also when I try to view it with amarok, it seems to unmount itself because the icon disappears from the desktop and its no longer in the file manager either. I'm using Ubuntu 9.04 with kernel 2.6.28-14-generic. Also using Xfce.

Sems your sansa runs in msc mode. (Drive letter in Windoze?)
Try to get it into mtp mode, which should be the default.
Use the latest firmware, too.

m0nk