I had the same problem about 4 or 5 months ago and I was able to re-create it. But If I'm not mistaken, here goes.
The Live update works/use an IE window to do the updates, and several scripts that Live update uses can cause it to go array if you do multiple updates at the same time. Like when you install the program for the first time and it needs to do multiple updates.
Try this, de-install you programs either NIS, NAV or Systemworks. When you run the Live updates, Only update the programs first and only one at the time. Dont update the definitions. Once all the programs are updated, run live update to update the NAV/NIS definitions or whatever. Then your Live update should run normally again.