Is webhcat running on localhost? I had exactly the same problem and the solution was to update the configuration in the hue.ini file (/etc/hue/config/hue.ini) and point the templeton_url property to point to the machine running webhcat process
[hcatalog]
templeton_url=http://node1:50111/templeton/v1/
security_enabled=false
You can test if the service is running by entering the following URL:
http://localhost:50111/templeton/v1/status
If you don’t get the response: {“status”:”ok”,”version”:”v1″} then you are pointing at the wrong server!
HTH