Problem with DC BACKUPS

[Vexnomad]

When my CDR programs reads the DC Backups or bootlegs that are self bootable it reads more than the CD capacity.

For example the CDs capacity is only 700mb but it reads 717mb or 808mb and then it doest not allow me to copy it onto another CD because my other CD only has a capacity of 700mb. Is this because there was a dummy file put onto the CD.