dcm_snoop: 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/dcm_snoop - from package: ctn

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

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