rdjpgcom: 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/rdjpgcom - from package: libjpeg-turbo

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

On Debian possible default full paths are:

/usr/bin/rdjpgcom - from package: libjpeg-turbo-progs

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

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