xwintoppm: 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 Debian possible default full paths are:

/usr/bin/xwintoppm - from package: mgp

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

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