Transcoding means it is having to convert the videos. You are going to dvd-video format? That will take some time.
When it is doing this, open Task Manager and look at the cpu usage. If it is pegged out, near 100%, then you know the program is still working.
Nero Vision would not be my choice for a conversion/authoring program, but it is convenient and newbie friendly. You might want to start looking at other options if you cannot get it to work in the manner you want.