upsd: 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/sbin/upsd - from package: nut

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

On Debian possible default full paths are:

/sbin/upsd - from package: nut-server

You may install the required package with command apt-get install {package}

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