cdffracinv: 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/cdffracinv - from package: cdftools

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