mk-slave-prefetch: 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-slave-prefetch - from package: maatkit

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

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