I use the latest 1.0.6 IDE on Win7 and loaded the latest MySensor libraries
https://github.com/mysensors/Arduino/
Added the attached libraries and they compiled just fine for me...

MyMQTTGateway.zip
Note1: Included is MyMQTTGateway and Pubsubclient.

Note2: This will make the gateway act as a MQTT client so you need Mosquitto (or similar) where you publish the topics from the gateway.

Note3: Remember to change the IP and Mac.