My bet is that you are trying to import a video only, elementary stream--which DVD-A won't accept. You have to create program streams (combined audio and video), even if the audio is silent.
Many encoders do indeed use the '.m2v' extension to designate the video elementary stream, but not all. It was not clear to me what setting was used in CCE. The file could be either elementary or program in nature. If it is a program stream, then it would help to know what parameters are being used to encode the video, because whatever it is, it's not compliant.
I believe the file would be considered an elementary stream.
In the enocder options I unchecked encode audio. The reason I did this is because I don't want CCE's audio, but I do want the high quality VBR video.
I then extract the audio seperatley to a wave file. I believe I tried naming the video file .m2v but DVDA still wouldn't take the file.
I find It hard to believe that this hasn't been complained about before. Don't most people use CCE for professional video?
By the way, if I do encode the audio it accepts the file.
DVDA requires a program stream and will not accept elementary streams.
Go ahead and let CCE encode the audio, this will make a program stream which DVDA will accept. Then you can very easily replace the audio track in DVDA with your PCM wave file.
The only problem with letting CCE encode the audio is I'm limited to CBR.
I get much better compression (almost 2-1) with VBR.
When using Premier 6.0 with CCE you are not allowed to encode audio and get A variable bit rate.
You can take your elementary stream m2v file and using a program called TMGPEnc, you can go to 'file'>'mpeg tools' and select the multiplex option. Select your video stream for the video option, and leave the audio blank. TMPGEnc will create a program stream with a 'dummy' audio component. Use the new program stream and associate it with the audio you want to use in DVD-A.