Have made a DVD with 10 audio tracks. When I "Make Movie" it renders but at end gives me error message "the requested plug-in does not have the necessary feature unlocked" (for ac3). Consequently it does not render the audio. Have removed all the audio tracts off line to confirm none have been corrupted and checked that they are all mp3 and work. Upon re-introduction get the same error. Have never had this problem over many years and many DVDs. What am I missing? Thanks.