ccdecrypt: 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/ccdecrypt - from package: ccrypt

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

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