I am so used to using Optimizer in VS11 to "finish" projects edited in the time line that I never questioned its actual purpose. I've just always used it, and never with HD in mind. I did try the DVD option you suggested and found that file would not work either. We produced another program using this encoder (it is located in a mobile truck ) and I burned a data disk right from the file the encoder made and it will work in Vegas and VS11 except now I have a "jumpy" frame problem. every 5-9 seconds the video (possibly audio) skips. This is not a Corel problem but an encoder problem. However, it could be why this file when processed through X4 will then not play properly - a gigo issue (garbage in garbage out.)
I have more testing to do. In the meantime I need to see if the problems are related or independent.