[Lauraine Graham- with the Lord]

Forgive me for mentioning something that you may have already thought of, but you do not mention the quality of your source material. If the discs from which you are compiling are damaged or dirty (or copied from a corrupted source) the file you generate will be corrupted. Clean copies cannot be got from a dirty source.

Also, the laser in your drive(s) must be cleaned on a regular basis. This is a process which can be forgotten when one is busy.

If the above can be elliminated as a reason for your problem I apologise for bringing it up.