Mixed Media message ? What's it mean+ WHY?

[gjayce]

I use a stand alone Samsung(Xbox creator software)/Verbatim discs ad have made about 40 discs without trouble. I just starting getting this message when I try the burnt games -"mixed media" and it wont pay- I have gotten the unreadable/non sytem disc errors, but what is this and any reason as to why I may be getting it? Thanks