Nrf24 Library problem

Hi guys,
I've just received 2 cheap NRF24L01 modules,
I've downloaded from github relative examples and relative library but when I try to upload one of the example sketch I got following error:

eg_read.pde: In function 'void setup()':
reg_read:23: error: 'Mirf' was not declared in this scope
reg_read:23: error: 'MirfHardwareSpi' was not declared in this scope
reg_read:31: error: 'RF_SETUP' was not declared in this scope

How can be ? any idea ?
Thank's for any help

Have you put the Mirf library in the Arduinos library folder, and then restarted Arduino ?

Yes, I've done it....
I have in my sketchbook a folder named "libraries" and I've copied into that folder Mirf lib files (.h - .cpp) as I've done previous with other libraries, but still don't work....):

Thank you for your help, problem solved.
was a libraries directory problem
:0