pdfjam: 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/pdfjam - from package: pdfjam

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

On Debian possible default full paths are:

/usr/bin/pdfjam - from package: texlive-extra-utils

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

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