pmlogextract: 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/pmlogextract - from package: pcp
/usr/libexec/pcp/bin/pmlogextract - from package: pcp

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

On Debian possible default full paths are:

/usr/bin/pmlogextract - from package: pcp
/usr/lib/pcp/bin/pmlogextract - from package: pcp

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

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