pnmcolormap: 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/pnmcolormap - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/pnmcolormap - from package: netpbm

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