qtiplot: 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/qtiplot - from package: qtiplot

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

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