I have installed two DVT Agents with Autoanswer. Both on two Servers. One Agent works fine, the other Agent accept the Call and then I get an Connection Error. In the Logfile of the Agent, I can see errors with the media type. I have installed a OCS MOC Client and this client works fine. I can call from another MOC Client to this Client with no audio problems. Also the NTFS Security ist ok. If I start the service, the DVT Agent will be shown as online.
Do you have DVT agent installed on your main OCS server? As I know DVT agent does not work if is placed there. You have to install it on some other server... for example if you have Monitoring server, then that would be a good choice.