Hello,

what are you trying to register? Which distro do you have? How did you install eucalyptus?

The script is trying to sync the keys with the remote (target) machine: depending on the above question, you could move the keys yourself, or you can let the script try again with the root user. Usually the eucalyptus user does not have a password, although you could give it one if you really want.

cheers
graziano