cdfstrconv: 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/cdfstrconv - from package: cdftools

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