pnmtopalm: 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/pnmtopalm - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/pnmtopalm - from package: netpbm

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

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