qrttoppm: 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/qrttoppm - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/qrttoppm - from package: netpbm

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

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