pbmtoepson: 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/pbmtoepson - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/pbmtoepson - from package: netpbm

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

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