dcm_x_disp: 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_x_disp - from package: ctn

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

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