pkcs15-crypt: 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 CentOS possible default full paths are:

/usr/bin/pkcs15-crypt - from package: opensc

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/pkcs15-crypt - from package: opensc

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

Error in other languages:
pkcs15-crypt: bevel nie gevind nie
pkcs15-crypt: comandă negăsită
pkcs15-crypt: comando não encontrado
pkcs15-crypt: commande introuvable
pkcs15-crypt: command not found
pkcs15-crypt: käsku ei ole
pkcs15-crypt: không tìm thấy lệnh
pkcs15-crypt: komanda nerasta
pkcs15-crypt: Kommando nicht gefunden.
pkcs15-crypt: kommandot finns inte
pkcs15-crypt: komut yok
pkcs15-crypt: nie znaleziono polecenia
pkcs15-crypt: níor aimsíodh an t-ordú
pkcs15-crypt: no se encontró la orden
pkcs15-crypt: no s'ha trobat l'ordre
pkcs15-crypt: opdracht niet gevonden
pkcs15-crypt: parancs nem található
pkcs15-crypt: perintah tidak ditemukan
pkcs15-crypt: príkaz nenájdený
pkcs15-crypt: příkaz nenalezen
pkcs15-crypt: команда не найдена
pkcs15-crypt: командата не е открита
pkcs15-crypt: 命令找不到
pkcs15-crypt: コマンドが見つかりません