I looking with a magnifying glass at the chip, i noted that this is NOT NRF24L01+ but just a NRF24L01 without the plus.
I used this smaller versions and they worked immediately. I_GATEWAY_READY message appeared. http://www.ebay.com/itm/2-4G-NRF24L01-PA-LNA-Wireless-Module-with-Ceramic-Antenna-1-27mm-/400746941364?pt=LH_DefaultDomain_0&hash=item5d4e610bb4
MySensors did post a warning on that: http://forum.mysensors.org/topic/728/radio-setup-give-check-wires/16
THREAD RESOLVED.
Thank you so much, scalz.
That solved my problem.
Just soldered them and now it works.
It really seems the arduino needs a good wired connection in order to work.
@Yveaux Thanks for your response. I guess that's it. I have to burn a bootloader first :-). I have a USBasp Programmer for that. Can you point me to a wiring diagram that shows how to connect the programmer to the circuit board?
I've added all the files manually so things should be there now (though I'd recommend grabbing things from github to preserve directory structure and get all the files).