ocamlrpcgen: command not found

Have You tried accessing the binary with the full path?

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 Debian possible default full paths are:

/usr/bin/ocamlrpcgen - from package: libocamlnet-ocaml-bin

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