ISO Burning problems

[antonio giulio]

Hi,

I'm trying to burn dvd-isos for debian and knoppix, but I got a bad md5 checksum for burned dvds. Md5sum for isos on hard-disk are perfect, but every burned iso returns a different checksum. I have tried with k3b and "cdrecord -dao" but I doesn't working. I'm using last updated unstable-debian.

Have you any idea?

Thanks,
Giulio