Job "bakup-smeserver" undefined usually means there is a mismatch between the name of the job and the name you typed.
Check the spelling with what is in the AFFA config file.
In /etc/affa, check that your script is named "server-backup.conf"
Check that the first line in the script is [server-backup]
A common source of confusion is when using _ (underscore) in stead of - (hyphen) or nothing at all:
eg backup_server or backup-server or backupserver
Or perhaps even a different name altogether.
Good luck
Cheers
Ian