ocamlc.opt: 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/ocamlc.opt - from package: ocaml

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

On Debian possible default full paths are:

/usr/bin/ocamlc.opt - from package: ocaml-native-compilers

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

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