dcmquant: 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/dcmquant - from package: dcmtk

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

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