Multi-touch on Asus X551C touchpad (Ubuntu 12.04)

I have a problem with installation of psmouse elantech-x551c dkms module on my Asus X551C laptop with Luna OS (built on Ubuntu 12.04). I'm using this instructions http://www.evilcodingmonkey.com/2014/01/23/ubuntu-activate-multi-touch-on-elantech/. But after running command

sudo dkms ldtarball psmouse-elantech-x551c.tar.gz

i get an error:

Error! psmouse-elantech-x551c is already added!
Aborting.

If i continue with

sudo dkms install -m psmouse -v elantech-x551c

the output is:

Kernel preparation unnecessary for this kernel. Skipping...

Building module:
cleaning build area....
make KERNELRELEASE=3.2.0-74-generic -C /lib/modules/3.2.0-74-generic/build M=/var/lib/dkms/psmouse/elantech-x551c/build/src psmouse.ko.....(bad exit status: 2)
Error! Bad return status for module build on kernel: 3.2.0-74-generic (x86_64)
Consult /var/lib/dkms/psmouse/elantech-x551c/build/make.log for more information.

The log file:

DKMS make.log for psmouse-elantech-x551c for kernel 3.2.0-74-generic (x86_64)

вівторок, 23 грудня 2014 20:56:38 +0200
make: Вхожу у каталог "/usr/src/linux-headers-3.2.0-74-generic"
  CC [M]  /var/lib/dkms/psmouse/elantech-x551c/build/src/psmouse-base.o
  CC [M]  /var/lib/dkms/psmouse/elantech-x551c/build/src/synaptics.o
/var/lib/dkms/psmouse/elantech-x551c/build/src/synaptics.c: In function ‘set_input_params’:
/var/lib/dkms/psmouse/elantech-x551c/build/src/synaptics.c:1278:31: error: ‘INPUT_MT_POINTER’ undeclared (first use in this function)
/var/lib/dkms/psmouse/elantech-x551c/build/src/synaptics.c:1278:31: note: each undeclared identifier is reported only once for each function it appears in
/var/lib/dkms/psmouse/elantech-x551c/build/src/synaptics.c:1278:3: error: too many arguments to function ‘input_mt_init_slots’
include/linux/input/mt.h:38:5: note: declared here
/var/lib/dkms/psmouse/elantech-x551c/build/src/synaptics.c:1286:3: error: too many arguments to function ‘input_mt_init_slots’

include/linux/input/mt.h:38:5: note: declared here
make[1]: *** [/var/lib/dkms/psmouse/elantech-x551c/build/src/synaptics.o] Помилка 1
make: *** [psmouse.ko] Помилка 2
make: Залишаю каталог "/usr/src/linux-headers-3.2.0-74-generic"

dkms status command returns:

psmouse, elantech-x551c: added

virtualbox, 4.1.12, 3.2.0-51-generic, x86_64: installed

Is there any suggestions what can I do? Do I need to remove added module at first? If yes, then how can I do this?

Regards