My computer just shut the power off while burning the second cd.. no other programs open. so clearly Heat problems. Acer TravelMate 5740G.
Right now with Linux Mint the fan is spinning as well without doing much work.. linux tends to run pretty hot on this and some other of my machines. But I never had sudden power-offs til now.
pBurn is a bit weird: copy a cd, so it reads the source, but when I insert a blank one to write on, another instance of pburn pops up asking me what to do with the cd. I dont know if it's your job to fix this, or if it's a feature of pburn

design wise, I think it's nice with xfce, but the tasbar is too densely filled. other decorations gives slightly more space between taskbuttons so you get more readability. but that is just cosmetics.. will go on testing.