Hi @neelam, welcome to the forum!
The dimmer example should work. If you want to use only the esp8266 with wifi (no nrf/rfm or other radio), you'll also need to add gateway settings from https://www.mysensors.org/build/esp8266_gateway
@scalz
in the second test i used that getting started code to test the radio modules with a library other than mysensors. and they worked. (That code is not mine, i suppose it use the maniacbug library).
So i did investigate to find the differences between mysensors and that library. Only after replacing, in mysensors, the enablefeatures with that code, i got the communication gw-node.
Now the RPi based on a new install of Raspbian Jessie, OpenHab 1.8.0 and Mosquitto is up and running and the ESP8266 MQTT client does connect without any problems. I have not changed anything in the code but Mosquitto is now based on the RPi repository for Jessie and not the mosquito_wheezy one. That seems to have fixed it so those versions are likely different but I have not put any time into checking this.
@fets So far, I have only built the 5x5 board (but the others should be schematically identical). The only issue I have found so far is that I cannot get the ISP port to work. But I have checked and I have an identical setup on the 1.0 board and that worked, so I suspect the programmer is too weak to drive the net on this one. So it is not a board-issue per se, and might only be an issue on the 5x5 board as routing is the most complex on that one due to the size.