ace-validator: 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/ace-validator - from package: golang-github-appc-spec

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

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