pbmtonokia: 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/pbmtonokia - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/pbmtonokia - from package: netpbm

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

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