Error "Function not implemented" when creating symbolic link

I'm trying to execute this command busybox ln -s "mydir/" "$PWD"/mylink in order to create a symbolic link from mydir; that, I am receiving the following error ln: /mnt/shell/emulated/0/mylink: Function not implemented! I've tried this in both adb shell and Android Terminal Emulator but to no avail. **Update:** Filesystem 1K-blocks Used Available Use% Mounted on tmpfs 496976 64 496912 0% /dev devpts 0 0 0 0% /dev/pts proc 0 0 0 0% /proc sysfs 0 0 0 0% /sys selinuxfs 0 0 0 0% /sys/fs/selinux debugfs 0 0 0 0% /sys/kernel/debug none 0 0 0 0% /acct tmpfs 496976 0 496976 0% /mnt/secure tmpfs 496976 0 496976 0% /mnt/asec tmpfs 496976 0 496976 0% /mnt/obb tmpfs 496976 0 496976 0% /mnt/fuse none 0 0 0 0% /dev/cpuctl /dev/block/mmcblk0p1 774064 420392 353672 54% /system /dev/block/mmcblk0p2 431368 94172 337196 22% /cache /dev/block/mmcblk0p8 59034284 5817516 53216768 10% /data /dev/fuse 59034284 5817516 53216768 10% /mnt/shell/emulated /dev/block/vold/179:49 31632380 25335912 6296468 80% /storage/sdcard1 //192.168.0.1/sdcard 30584780 23082428 7502352 75% /mnt/routersd //192.168.0.1/sdcard 30584780 23082428 7502352 75% /mnt/shell/emulated/0/routersd