What has your question got to do with the WiFi shield - as you've posted in that category?
You should move it somewhere more appropriate - maybe the Networking, Protocols and Devices section.
Have you read through the nRF24L01 tutorial(s) here to establish that your radios are working:
Those rectangular 9V batteries are a very poor choice for powering your project, and are likely the source of your problem. I would suggest a different power source. If you need to start with 9V, then 6x AA batteries in a battery holder would suffice.