ADAL authentication fails (version 1.0.2)

I am using ADAL -  Microsoft.IdentityModel.Clients.ActiveDirectory version 1.0.2.  

I am failing consistently with the following error:

  AADSTS90014: The request body must contain the following parameter: 'client_secret or client_assertion'.

At the line

AuthenticationResult r = ac.AcquireToken(resourceURI, clientID, new Uri(clientReturnURI));

The dialog shows up OK, after I sign, in I get the error.

Note:

I am following Vittorio's example in

http://www.cloudidentity.com/blog/2013/09/16/getting-acquainted-with-authenticationresult/

Sam