opal_wrapper: 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 Debian possible default full paths are:

/usr/bin/opal_wrapper - from package: libopenmpi-dev

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

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