qtchooser: 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/qtchooser - from package: qtchooser

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

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