Game Backup

[Slik]

When I try and backup CS:Source, it gives me four disk files. And When I try to install it on my other machine, its asking me for a disk 5.dat which I dont have. I also cant download the game because of a steam error.
can someone please help me?

EDIT: OK NEVERMIND, I MANAGED TO DO THIS A DIFFERENT WAY.
I COMPRESSED THE FILES WITH WINRAR AND PUT THEM ON A CD.