mk-parallel-restore: 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:

/usr/bin/mk-parallel-restore - from package: maatkit

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

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