Fedora 18 mag keine ISO Files

Hello,
I've installed Fedora 18 on my PC and I want to save some files of my second HDD to an extern one. But if I copy some ISO Files from one to the other HDD Fedora means: "Error splicing file: File too large"
Can't I move some 6GB ISO Files from one to an other HDD?
THX@ALL Plermpel