Bot Service is not working with Node.js . Error cannot find module 'botbuilder'

I had this same problem and solved it by running npm install in kudu console.

Go to your Bot Service's Settings-tab and click to open "Advanced settings". There you can find "Advanced Tools" (kudu) under Development tools. Open Debug Console and cd to the folder where you have package.json (for me it was D:\home\site\wwwroot\messages) and run npm install.

After that you can communicate with the bot in dev.botframework.com although the chat interface won't still work in Azure portal.