pdfjam-slides6up: 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-slides6up - from package: pdfjam

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

On Debian possible default full paths are:

/usr/bin/pdfjam-slides6up - from package: texlive-extra-utils

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

Error in other languages:
pdfjam-slides6up: bevel nie gevind nie
pdfjam-slides6up: comandă negăsită
pdfjam-slides6up: comando não encontrado
pdfjam-slides6up: commande introuvable
pdfjam-slides6up: command not found
pdfjam-slides6up: käsku ei ole
pdfjam-slides6up: không tìm thấy lệnh
pdfjam-slides6up: komanda nerasta
pdfjam-slides6up: Kommando nicht gefunden.
pdfjam-slides6up: kommandot finns inte
pdfjam-slides6up: komut yok
pdfjam-slides6up: nie znaleziono polecenia
pdfjam-slides6up: níor aimsíodh an t-ordú
pdfjam-slides6up: no se encontró la orden
pdfjam-slides6up: no s'ha trobat l'ordre
pdfjam-slides6up: opdracht niet gevonden
pdfjam-slides6up: parancs nem található
pdfjam-slides6up: perintah tidak ditemukan
pdfjam-slides6up: príkaz nenájdený
pdfjam-slides6up: příkaz nenalezen
pdfjam-slides6up: команда не найдена
pdfjam-slides6up: командата не е открита
pdfjam-slides6up: 命令找不到
pdfjam-slides6up: コマンドが見つかりません