freefoam-plot3dToFoam: 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

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-plot3dToFoam - from package: freefoam

You may install the required package with command apt-get install {package}
Error in other languages:
freefoam-plot3dToFoam: bevel nie gevind nie
freefoam-plot3dToFoam: comandă negăsită
freefoam-plot3dToFoam: comando não encontrado
freefoam-plot3dToFoam: commande introuvable
freefoam-plot3dToFoam: command not found
freefoam-plot3dToFoam: käsku ei ole
freefoam-plot3dToFoam: không tìm thấy lệnh
freefoam-plot3dToFoam: komanda nerasta
freefoam-plot3dToFoam: Kommando nicht gefunden.
freefoam-plot3dToFoam: kommandot finns inte
freefoam-plot3dToFoam: komut yok
freefoam-plot3dToFoam: nie znaleziono polecenia
freefoam-plot3dToFoam: níor aimsíodh an t-ordú
freefoam-plot3dToFoam: no se encontró la orden
freefoam-plot3dToFoam: no s'ha trobat l'ordre
freefoam-plot3dToFoam: opdracht niet gevonden
freefoam-plot3dToFoam: parancs nem található
freefoam-plot3dToFoam: perintah tidak ditemukan
freefoam-plot3dToFoam: príkaz nenájdený
freefoam-plot3dToFoam: příkaz nenalezen
freefoam-plot3dToFoam: команда не найдена
freefoam-plot3dToFoam: командата не е открита
freefoam-plot3dToFoam: 命令找不到
freefoam-plot3dToFoam: コマンドが見つかりません