netxml-ups: 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:

/sbin/netxml-ups - from package: nut-xml

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