pmloglabel: 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/pmloglabel - from package: pcp

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

On Debian possible default full paths are:

/usr/bin/pmloglabel - from package: pcp

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

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