pki-setup-proxy: 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/pki-setup-proxy - from package: pki-setup

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

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