The MKIV maps are on a single DVD for North America and a single DVD for Europe as far as I know. The MKIV is capable of reading CD maps as well, but you would be wasting one of the biggest advantages of the MKIV by using CDs instead of the DVD maps.

Maybe some countries maps don't require a DVD for all the info, so they just use a CD. I see you have an Australia flag next to your name...maybe Australia falls into this category. I also see the Sweden flag? Where are you located...I would think Sweeden would be on DVD, but maybe not.