pmnsdel: 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/libexec/pcp/bin/pmnsdel - from package: pcp

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

On Debian possible default full paths are:

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

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

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