except: 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

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/except - from package: qmail
/var/lib/qmail/bin/except - from package: qmail

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