mpicc.openmpi: 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/mpicc.openmpi - from package: libopenmpi-dev

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