What about `ls -l /Mount/Media/System/Links/Executables`? I believe that's the file it's looking for, since /Mount/Media is the new root. You can't run an executable that's outside that new root path... that's sort of the point of a chroot :-). What are you trying to accomplish? There might be a different way to get it to work.
If you really want to verify that the chroot command itself works, try the actual root directory: `chroot /`. To get into any other directory, in addition to all the necessary libraries and executables you'd need copies of in the new root to have a working environment, you'd also need a couple Kernel directories, according to Lucas's tip on the mailing list: http://lists.gobolinux.org/pipermail/gobolinux-users/2008-January/006921.html.
When you chroot into a directory, you enter the shell within it. That error means there's no shell there (i.e. /Mount/Media/System/Links/Executables/zsh doesn't exist). You can specify an alternative command with `chroot /Mount/Media <command>`.
If you want to run a shell, you have to put a copy of it in the right place, or bind-mount it in. I'm not sure why you'd want to do that in /M/M, but the ability is there if you want to.