NullPointerException when exchanging code for oAuth access token
I have a new install of OAM 11.1.2.3 and are following the guide at http://www.ateam-oracle.com/implementing-oauth-2-with-oracle-access-manager-oauth-services-part-iv/ to test the 3-leg oAuth flow.
I am able to obtain the auth code, however when attempting to exchange this for the oAuth access token, I get the following error, any ideas as to what this means?
java.lang.NullPointerException
at oracle.security.idaas.oauth.token.TokenRequest.isRequiredClientAuthentication(TokenRequest.java:688)
at oracle.security.idaas.oauth.token.TokenRequest.validateAndSetClientInfo(TokenRequest.java:607)
at oracle.security.idaas.oauth.token.TokenRequest.<init>(TokenRequest.java:502)
at oracle.security.idaas.oauth.token.impl.OAuthTokenRequestHandler.processRequestInternalNew(OAuthTokenRequestHandler.java:430)