pamtotga: 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/pamtotga - from package: netpbm-progs

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