gnupg-pkcs11-scd: 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/gnupg-pkcs11-scd - from package: gnupg-pkcs11-scd

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

Error in other languages:
gnupg-pkcs11-scd: bevel nie gevind nie
gnupg-pkcs11-scd: comandă negăsită
gnupg-pkcs11-scd: comando não encontrado
gnupg-pkcs11-scd: commande introuvable
gnupg-pkcs11-scd: command not found
gnupg-pkcs11-scd: käsku ei ole
gnupg-pkcs11-scd: không tìm thấy lệnh
gnupg-pkcs11-scd: komanda nerasta
gnupg-pkcs11-scd: Kommando nicht gefunden.
gnupg-pkcs11-scd: kommandot finns inte
gnupg-pkcs11-scd: komut yok
gnupg-pkcs11-scd: nie znaleziono polecenia
gnupg-pkcs11-scd: níor aimsíodh an t-ordú
gnupg-pkcs11-scd: no se encontró la orden
gnupg-pkcs11-scd: no s'ha trobat l'ordre
gnupg-pkcs11-scd: opdracht niet gevonden
gnupg-pkcs11-scd: parancs nem található
gnupg-pkcs11-scd: perintah tidak ditemukan
gnupg-pkcs11-scd: príkaz nenájdený
gnupg-pkcs11-scd: příkaz nenalezen
gnupg-pkcs11-scd: команда не найдена
gnupg-pkcs11-scd: командата не е открита
gnupg-pkcs11-scd: 命令找不到
gnupg-pkcs11-scd: コマンドが見つかりません