rrestore: 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 CentOS possible default full paths are:

/sbin/rrestore - from package: dump

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/sbin/rrestore - from package: dump

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

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