PKCS12Export: 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 CentOS possible default full paths are:

/usr/bin/PKCS12Export - from package: pki-java-tools

You may install the required package with command yum install {package}
Error in other languages:
PKCS12Export: bevel nie gevind nie
PKCS12Export: comandă negăsită
PKCS12Export: comando não encontrado
PKCS12Export: commande introuvable
PKCS12Export: command not found
PKCS12Export: käsku ei ole
PKCS12Export: không tìm thấy lệnh
PKCS12Export: komanda nerasta
PKCS12Export: Kommando nicht gefunden.
PKCS12Export: kommandot finns inte
PKCS12Export: komut yok
PKCS12Export: nie znaleziono polecenia
PKCS12Export: níor aimsíodh an t-ordú
PKCS12Export: no se encontró la orden
PKCS12Export: no s'ha trobat l'ordre
PKCS12Export: opdracht niet gevonden
PKCS12Export: parancs nem található
PKCS12Export: perintah tidak ditemukan
PKCS12Export: príkaz nenájdený
PKCS12Export: příkaz nenalezen
PKCS12Export: команда не найдена
PKCS12Export: командата не е открита
PKCS12Export: 命令找不到
PKCS12Export: コマンドが見つかりません