Are you using Nero Vision to convert to DVD format?
When you select 'Burn' the program freezes?
Ive had problems with encoders 'freezing' before (not Nero, though). I found out it was because of the CODEC PACKS that I installed.
Now, I use a program called AVICodec (free). All you do is drag and drop files. It will tell you what codecs are necessary, if you have them, and has links to where you can get them if you don't have them.
This way, you are downloading only the individual codecs that you need. If you are downloading videos with LW, I would recommend the DivX and XviD codecs to start.
Good Luck
Dano