dtrace: 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/dtrace - from package: systemtap-sdt-devel

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

On Debian possible default full paths are:

/usr/bin/dtrace - from package: systemtap-sdt-dev

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

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