I thought to write down five steps one should take that could free himself from many troubles with Nero as well as other programs:
1) Ensure your PC is virus free. Norton Antivirus or Kaspersky or McAfee. Generally any that has daily updates to virus bases.
2) Update your recorder's firmware bios. Be carefull to select the correct firmware for your recorder model. If the update is done via dos, be carefull where your recorder is mounted(Primary master or slave or Secondary master or slave e.t.c). If the update is done from within windows, then usually the proccess is automated. Take second thought on updating firmware, only if you can not rollback back to previous firmware versions(this is the case with some pioneer recorders).
3) Update Nero, or rollback to an older version of nero if you know that you didnt have any kind of problem with the older version. Before you rollback use a registry cleaning program to get rid of any registry setting left by the other version of nero.
4) Use the recommended media by your recorders manufacturer and try burning at lower speeds if you have other media.
5) Disable any kind of background applications including antivirus shields. This maybe seems opposite to (1) but it isnt. You can choose the proper time to disable, like say before pressing the burn button.
From my little experience in this forum, most of the problems are gone by doing one or more of the above five steps. I hope they come helpfull to all of you.