pq_ctndisp: 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/pq_ctndisp - from package: ctn

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

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