appendpdf: 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 Debian possible default full paths are:

/usr/bin/appendpdf - from package: libcam-pdf-perl

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

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