ocamlopt: 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/ocamlopt - from package: ocaml

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

On Debian possible default full paths are:

/usr/bin/ocamlopt - from package: ocaml-nox

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

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