pysaml2-mdexport: 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/pysaml2-mdexport - from package: python-pysaml2

You may install the required package with command apt-get install {package}
Error in other languages:
pysaml2-mdexport: bevel nie gevind nie
pysaml2-mdexport: comandă negăsită
pysaml2-mdexport: comando não encontrado
pysaml2-mdexport: commande introuvable
pysaml2-mdexport: command not found
pysaml2-mdexport: käsku ei ole
pysaml2-mdexport: không tìm thấy lệnh
pysaml2-mdexport: komanda nerasta
pysaml2-mdexport: Kommando nicht gefunden.
pysaml2-mdexport: kommandot finns inte
pysaml2-mdexport: komut yok
pysaml2-mdexport: nie znaleziono polecenia
pysaml2-mdexport: níor aimsíodh an t-ordú
pysaml2-mdexport: no se encontró la orden
pysaml2-mdexport: no s'ha trobat l'ordre
pysaml2-mdexport: opdracht niet gevonden
pysaml2-mdexport: parancs nem található
pysaml2-mdexport: perintah tidak ditemukan
pysaml2-mdexport: príkaz nenájdený
pysaml2-mdexport: příkaz nenalezen
pysaml2-mdexport: команда не найдена
pysaml2-mdexport: командата не е открита
pysaml2-mdexport: 命令找不到
pysaml2-mdexport: コマンドが見つかりません