cdfmean: 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/cdfmean - from package: cdftools

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

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