safe_camlp4: 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/safe_camlp4 - from package: ocaml-findlib

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

On Debian possible default full paths are:

/usr/bin/safe_camlp4 - from package: ocaml-findlib

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

Error in other languages:
safe_camlp4: bevel nie gevind nie
safe_camlp4: comandă negăsită
safe_camlp4: comando não encontrado
safe_camlp4: commande introuvable
safe_camlp4: command not found
safe_camlp4: käsku ei ole
safe_camlp4: không tìm thấy lệnh
safe_camlp4: komanda nerasta
safe_camlp4: Kommando nicht gefunden.
safe_camlp4: kommandot finns inte
safe_camlp4: komut yok
safe_camlp4: nie znaleziono polecenia
safe_camlp4: níor aimsíodh an t-ordú
safe_camlp4: no se encontró la orden
safe_camlp4: no s'ha trobat l'ordre
safe_camlp4: opdracht niet gevonden
safe_camlp4: parancs nem található
safe_camlp4: perintah tidak ditemukan
safe_camlp4: príkaz nenájdený
safe_camlp4: příkaz nenalezen
safe_camlp4: команда не найдена
safe_camlp4: командата не е открита
safe_camlp4: 命令找不到
safe_camlp4: コマンドが見つかりません