freefoam-Lambda2: 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/freefoam-Lambda2 - from package: freefoam

You may install the required package with command apt-get install {package}
Error in other languages:
freefoam-Lambda2: bevel nie gevind nie
freefoam-Lambda2: comandă negăsită
freefoam-Lambda2: comando não encontrado
freefoam-Lambda2: commande introuvable
freefoam-Lambda2: command not found
freefoam-Lambda2: käsku ei ole
freefoam-Lambda2: không tìm thấy lệnh
freefoam-Lambda2: komanda nerasta
freefoam-Lambda2: Kommando nicht gefunden.
freefoam-Lambda2: kommandot finns inte
freefoam-Lambda2: komut yok
freefoam-Lambda2: nie znaleziono polecenia
freefoam-Lambda2: níor aimsíodh an t-ordú
freefoam-Lambda2: no se encontró la orden
freefoam-Lambda2: no s'ha trobat l'ordre
freefoam-Lambda2: opdracht niet gevonden
freefoam-Lambda2: parancs nem található
freefoam-Lambda2: perintah tidak ditemukan
freefoam-Lambda2: príkaz nenájdený
freefoam-Lambda2: příkaz nenalezen
freefoam-Lambda2: команда не найдена
freefoam-Lambda2: командата не е открита
freefoam-Lambda2: 命令找不到
freefoam-Lambda2: コマンドが見つかりません