backup-labeltape: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/backup-labeltape - from package: chiark-backup

You may install the required package with command apt-get install {package}

Error in other languages:
backup-labeltape: bevel nie gevind nie
backup-labeltape: comandă negăsită
backup-labeltape: comando não encontrado
backup-labeltape: commande introuvable
backup-labeltape: command not found
backup-labeltape: käsku ei ole
backup-labeltape: không tìm thấy lệnh
backup-labeltape: komanda nerasta
backup-labeltape: Kommando nicht gefunden.
backup-labeltape: kommandot finns inte
backup-labeltape: komut yok
backup-labeltape: nie znaleziono polecenia
backup-labeltape: níor aimsíodh an t-ordú
backup-labeltape: no se encontró la orden
backup-labeltape: no s'ha trobat l'ordre
backup-labeltape: opdracht niet gevonden
backup-labeltape: parancs nem található
backup-labeltape: perintah tidak ditemukan
backup-labeltape: príkaz nenájdený
backup-labeltape: příkaz nenalezen
backup-labeltape: команда не найдена
backup-labeltape: командата не е открита
backup-labeltape: 命令找不到
backup-labeltape: コマンドが見つかりません