qtmail: command not found

Have You tried accessing the binary with the full path?

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/lib/debug/usr/bin/qtmail - from package: qmf-dbg
/usr/bin/qtmail - from package: qmf-examples

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