plowprobe: 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/plowprobe - from package: plowshare

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

On Debian possible default full paths are:

/usr/bin/plowprobe - from package: plowshare4

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

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