pkpgcounter: 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/bin/pkpgcounter - from package: pkpgcounter

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

On Debian possible default full paths are:

/usr/bin/pkpgcounter - from package: pkpgcounter

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

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