jpeg2ktopam: command not found

Have You tried accessing the binary with the full path?

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/jpeg2ktopam - from package: netpbm-progs

You may install the required package with command yum install {package}
Error in other languages:
jpeg2ktopam: bevel nie gevind nie
jpeg2ktopam: comandă negăsită
jpeg2ktopam: comando não encontrado
jpeg2ktopam: commande introuvable
jpeg2ktopam: command not found
jpeg2ktopam: käsku ei ole
jpeg2ktopam: không tìm thấy lệnh
jpeg2ktopam: komanda nerasta
jpeg2ktopam: Kommando nicht gefunden.
jpeg2ktopam: kommandot finns inte
jpeg2ktopam: komut yok
jpeg2ktopam: nie znaleziono polecenia
jpeg2ktopam: níor aimsíodh an t-ordú
jpeg2ktopam: no se encontró la orden
jpeg2ktopam: no s'ha trobat l'ordre
jpeg2ktopam: opdracht niet gevonden
jpeg2ktopam: parancs nem található
jpeg2ktopam: perintah tidak ditemukan
jpeg2ktopam: príkaz nenájdený
jpeg2ktopam: příkaz nenalezen
jpeg2ktopam: команда не найдена
jpeg2ktopam: командата не е открита
jpeg2ktopam: 命令找不到
jpeg2ktopam: コマンドが見つかりません