I am successfully able to log into the facebook / custom oauth login and then authenticate / authorize the user credentials. But, when the callback happens (http:///callback/facebook?xxx), it fails saying that there is an error while processing request. This comes from the java code 'processRequest()' of oauthcallback.java class.
Essentially, this takes the oauthtoken_url as the input...but fails when it tries to execute the url...not sure if the issue is in the code which picks this up or its the way we are passing the oauthtoken url...need help here !!