undefined reference to `xnGetRefContextFromNodeHandle'

This errors comes together with all the rest. The problem is the g++ linker requires the OpenNI library to be explicitly declared.

g++ ...................  -lOpenNI

In eclipse:

1) Go to Project Properties of the project:

2) Add OpenNI to the G++ Linker Libraries.

Reference

https://groups.google.com/forum/#!msg/openni-dev/0-lOIyJn0DY/0pQheC2oth4J