Emby refuses to play videos encoded with codecs I've entered into the <CodecProfiles> portion of the DLNA profile.
This one for example...
This also happens if there's no DirectPlayProfile for the codec. For example, trying to play this to my Sony Bravia causes the error...
Worth mentioning, I was getting this error on version .26 too. I've rolled back as I found DLNA unreliable and the wife wasn't happy
Log with error, and my DLNA profile are attached to this post.