ppswatch: 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 Debian possible default full paths are:

/usr/bin/ppswatch - from package: pps-tools

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

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