pwqgen: 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/bin/pwqgen - from package: passwdqc

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