rosrun openni_tracker openni_tracker

In a terminal run 

$ roscore.

in another terminal, run 

$ rosrun openni_tracker openni_tracker,

problems happened.

 1. Find user generator failed: This operation is invalid!

1. Download the NiTE v1.5.2.23 binary package from one of the following links depending on whether you are using a 32-bit or 64-bit installation of Ubuntu:

   a. 32-bit: http://www.openni.org/wp-content/uploads/2013/10/NITE-Bin-Linux-x86-v1.5.2.23.tar.zip
   b. 64-bit: http://www.openni.org/wp-content/uploads/2013/10/NITE-Bin-Linux-x64-v1.5.2.23.tar.zip

2. Unzip and extract the archive to a location of your choice (e.g. ~/tmp)

3. The unzipped archive is actually another archive in bz2 format so unzip and extract the archive to the same location as in Step 2.

4. The resulting folder should be called NITE-Bin-Dev-Linux-x64-v1.5.2.23 (64-bit) or NITE-Bin-Linux-x86-v1.5.2.23 (32-bit)/ Move into this folder and then run the uninstall.sh script followed by the install.sh scripts. For the 64-bit version this would look like the following:

   $ cd ~/tmp/NITE-Bin-Dev-Linux-x64-v1.5.2.23
   $ sudo ./uninstall.sh
   $ sudo ./install.sh

I downloaded the NITE from this website:

http://code.google.com/p/simple-openni/downloads/detail?name=OpenNI_NITE_Installer-Linux32-0.27.zip&can=3&q=

Afterthat, new problem happened. 

2. Can't create any node of the requested type!

Solution: download 5 64bit .zip documents from OPENNI SDK HISTORY.

http://www.openni.ru/openni-sdk/openni-sdk-history-2/

Remember that my ubuntu is 64 bits, not 32 bits. Looking into the bits of ubuntu: $ uname-a

Installing them in the folder: /tmp.

Solved!