stap-prep: 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/stap-prep - from package: systemtap-client
/usr/bin/stap-prep - from package: systemtap-devel

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

On Debian possible default full paths are:

/usr/bin/stap-prep - from package: systemtap

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

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