NeroVison4 doesnt burn nero digital?

Ok so usually i burn lots of fansubs from avi to mp4 to border it right and so on. I use nero recode the latest version and convert it to mp4. The weird thing is after that i drag the file to nerovision to burn and it just freezes… The bar loads the movie and it feels like it got added but instead just freezes… any ideas as to whats going on? The fansub has a H.264 video stream and an audio stream of AAC LC. maybe the problem is the h264? Is there anyway around it or am i stuck like this D:?