You could try doing a repair of XP to start with at the run prompt type sfc /scannow and have your xp disk to hand. This will check windows files and replace any corrupt ones.
Have you always had nero and xp burning working ok together? Have you just added nero to the system recently as it could be a clash between them thats causing the problem.
You might get more help with this problem if you post it in the helproom and tick this one.