pwrkap_main: 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/pwrkap_main - from package: pwrkap

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

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