Backing up system

[GMS S]

Hi,
With the SystemRescueCd ,typing xinit in the terminal a graphical interface with the terminal appears.
There typing partimage got the partimage window.
Giving a filename like "backup" the backing up process starts.
After a while it prompts that there is no space left.

The current directory was like this: [root at localhost/root]#

What should I do then?
Where should I save the backup file?
Can anyone give any idea?