usbhid-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/usbhid-ups - from package: nut

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