I tried by mistake to save the clonezilla image to a partition with only a little free space, so I got a "disk full" error during the process.
So, I found myself looking at the console who was writing "Press "Enter" to continue.
Well, pressing "Enter" or any othe key combination didn't worked and clonezilla was unresponsible.
The only keyboard input that worked was ctrl-alt-del and clonezilla rebooted.
Steps to reproduce:
1) Try to backup to a partition with very little space.
2) Wait until you got the "disk full" and "press enter to continue" error.
3) Try to input "Enter". Inputing "Enter", don't works.
(I'm using the latest stable ubuntu based x64 version).