check-zone-expiration: 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/check-zone-expiration - from package: dnssec-tools

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

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