pgmminkowski: 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/pgmminkowski - from package: netpbm-progs

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

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